doc/tutorial: add title with file names to code blocks (ent#2430)

doc/md/tutorial-todo-gql-field-collection.md

@@ -73,7 +73,7 @@ and for the node(s) API.
 Before we go over the example, we change the `ent.Client` to run in debug mode in the `Todos` resolver and restart
 our GraphQL server:
 
-```diff
+```diff title="todo.resolvers.go"
 func (r *queryResolver) Todos(ctx context.Context, after *ent.Cursor, first *int, before *ent.Cursor, last *int, orderBy *ent.TodoOrder) (*ent.TodoConnection, error) {
 -	return r.client.Todo.Query().
 +	return r.client.Debug().Todo.Query().
@@ -123,7 +123,7 @@ SELECT DISTINCT `todos`.`id`, `todos`.`text`, `todos`.`created_at`, `todos`.`sta
 Let's see how Ent can automatically solve our problem. All we need to do is to add the following
 `entql` annotations to our edges:
 
-```diff
+```diff title="ent/schema/todo.go"
 func (Todo) Edges() []ent.Edge {
 	return []ent.Edge{
 		edge.To("parent", Todo.Type).
@@ -139,9 +139,9 @@ The `Bind()` annotation is now enabled by default, use `Unbind()` to opt-out.
 :::
 
 After adding these annotations, `entgql` will do the binding mentioned in the [section](#ent-solution) above. Additionally, it
-will also generate edge-resolvers for the nodes under the `edge.go` file:
+will also generate edge-resolvers for the nodes under the `gql_edge.go` file:
 
-```go
+```go title="ent/gql_edge.go"
 func (t *Todo) Children(ctx context.Context) ([]*Todo, error) {
 	result, err := t.Edges.ChildrenOrErr()
 	if IsNotLoaded(err) {

doc/md/tutorial-todo-gql-mutation-input.md

@@ -26,7 +26,7 @@ The Ent framework accepts external templates that can extend or override the def
 code generator. In the template below, we generate 2 input types (`CreateTodoInput` and `UpdateTodoInput`) for the
 GraphQL mutations, and add additional methods on the different builders to accept these objects as an input type.
 
-```gotemplate
+```gotemplate title="ent/template/mutation_input.tmpl"
 {{ range $n := $.Nodes }}
     {{ $input := print "Create" $n.Name "Input" }}
     // {{ $input }} represents a mutation input for creating {{ plural $n.Name | lower }}.
@@ -113,7 +113,7 @@ go generate ./...
 
 You may have noticed that Ent generated a new file `ent/mutation_input.go` with the following content:
 
-```go
+```go title="ent/template/mutation_input.go"
 // Code generated by entc, DO NOT EDIT.
 
 package ent
@@ -160,7 +160,7 @@ func (i *UpdateTodoInput) Mutate(m *TodoMutation) {
 The new generated Go types are the GraphQL mutation types. Let's define them manually in the GraphQL schema and `gqlgen`
 will map them automatically.
 
-```graphql
+```graphql title="todo.graphql"
 # Define an input type for the mutation below.
 # https://graphql.org/learn/schema/#input-types
 #
@@ -207,7 +207,7 @@ go generate ./...
 
 The result is as follows:
 
-```go
+```go title="todo.resolvers.go"
 func (r *mutationResolver) CreateTodo(ctx context.Context, input ent.CreateTodoInput) (*ent.Todo, error) {
 	panic(fmt.Errorf("not implemented"))
 }
@@ -225,7 +225,7 @@ func (r *mutationResolver) UpdateTodos(ctx context.Context, ids []int, input ent
 
 The `Set<F>` calls in the `CreateTodo` resolver are replaced with one call named `SetInput`:
 
-```diff
+```diff title="todo.resolvers.go"
 func (r *mutationResolver) CreateTodo(ctx context.Context, input ent.CreateTodoInput) (*ent.Todo, error) {
 	return ent.FromContext(ctx).Todo.
 		Create().
@@ -240,7 +240,7 @@ func (r *mutationResolver) CreateTodo(ctx context.Context, input ent.CreateTodoI
 
 The rest of the resolvers (`UpdateTodo` and `UpdateTodos`) will be implemented as follows:
 
-```diff
+```diff title="todo.resolvers.go"
 func (r *mutationResolver) CreateTodo(ctx context.Context, input ent.CreateTodoInput) (*ent.Todo, error) {
 	return ent.FromContext(ctx).Todo.Create().SetInput(input).Save(ctx)
 }

doc/md/tutorial-todo-gql-node.md

@@ -39,7 +39,7 @@ go run ./cmd/todo/
 
 Ent supports the Node interface through its GraphQL integration. By following a few simple steps you can add support for it in your application. We start by adding the `Node` interface to our GraphQL schema:
 
-```diff
+```diff title="todo.graphql"
 +interface Node {
 +    id: ID!
 +}
@@ -64,7 +64,7 @@ type Query {
 
 Then, we tell gqlgen that Ent provides this interface by editing the `gqlgen.yaml` file as follows:
 
-```diff
+```diff title="gqlgen.yml"
 # This section declares type mapping between the GraphQL and Go type systems.
 models:
   # Defines the ID field as Go 'int'.
@@ -88,7 +88,7 @@ go generate ./...
 Like before, we need to implement the GraphQL resolve in the `todo.resolvers.go` file, but that's simple.
 Let's replace the default resolvers with the following:
 
-```go
+```go title="todo.resolvers.go"
 func (r *queryResolver) Node(ctx context.Context, id int) (ent.Noder, error) {
 	return r.client.Noder(ctx, id)
 }

doc/md/tutorial-todo-gql-paginate.md

@@ -54,7 +54,7 @@ Ordering can be defined on any comparable field of ent by annotating it with `en
 Note that the given `OrderField` name must match its enum value in GraphQL schema (see
 [next section](#define-ordering-types-in-graphql-schema) below).
 
-```go
+```go title="ent/schema/todo.go"
 func (Todo) Fields() []ent.Field {
     return []ent.Field{
 		field.Text("text").
@@ -91,7 +91,7 @@ func (Todo) Fields() []ent.Field {
 Next, we need to define the ordering types along with the [Relay Connection Types](https://relay.dev/graphql/connections.htm#sec-Connection-Types)
 in the GraphQL schema:
 
-```graphql
+```graphql title="todo.graphql"
 # Define a Relay Cursor type:
 # https://relay.dev/graphql/connections.htm#sec-Cursor
 scalar Cursor
@@ -161,7 +161,7 @@ go generate ./...
 
 Head over to the `Todos` resolver and update it to pass `orderBy` argument to `.Paginate()` call:
 
-```go
+```go title="todo.resolvers.go"
 func (r *queryResolver) Todos(ctx context.Context, after *ent.Cursor, first *int, before *ent.Cursor, last *int, orderBy *ent.TodoOrder) (*ent.TodoConnection, error) {
 	return r.client.Todo.Query().
 		Paginate(ctx, after, first, before, last,

doc/md/tutorial-todo-gql-tx-mutation.md

@@ -30,13 +30,13 @@ we follow these steps:
 1\. Edit the `cmd/todo/main.go` and add to the GraphQL server initialization the `entgql.Transactioner` handler as
 follows:
 
-```diff
+```diff title="cmd/todo/main.go"
 srv := handler.NewDefaultServer(todo.NewSchema(client))
 +srv.Use(entgql.Transactioner{TxOpener: client})
 ```
 
 2\. Then, in the GraphQL mutations, use the client from context as follows:
-```diff
+```diff title="todo.resolvers.go"
 func (mutationResolver) CreateTodo(ctx context.Context, todo TodoInput) (*ent.Todo, error) {
 +	client := ent.FromContext(ctx)
 +	return client.Todo.

doc/md/tutorial-todo-gql.md

@@ -27,7 +27,7 @@ go run ./cmd/todo/
 This tutorial begins where the previous one ended (with a working Todo-list schema). We start by creating a simple GraphQL schema for our todo list, then install the [99designs/gqlgen](https://github.com/99designs/gqlgen)
 package and configure it. Let's create a file named `todo.graphql` and paste the following:
 
-```graphql
+```graphql title="todo.graphql"
 # Maps a Time GraphQL scalar to a Go time.Time struct.
 scalar Time
 
@@ -80,7 +80,7 @@ go get github.com/99designs/gqlgen
 The gqlgen package can be configured using a `gqlgen.yml` file that it automatically loads from the current directory.
 Let's add this file. Follow the comments in this file to understand what each config directive means:
 
-```yaml
+```yaml title="gqlgen.yml"
 # schema tells gqlgen where the GraphQL schema is located.
 schema:
   - todo.graphql
@@ -149,7 +149,7 @@ go get entgo.io/contrib/entgql
 
 **2\.** Create a new Go file named `ent/entc.go`, and paste the following content:
 
-```go
+```go title="ent/entc.go"
 // +build ignore
 
 package main
@@ -178,7 +178,7 @@ func main() {
 
 **3\.** Edit the `ent/generate.go` file to execute the `ent/entc.go` file:
 
-```go
+```go title="ent/generate.go"
 package ent
 
 //go:generate go run entc.go
@@ -190,7 +190,7 @@ Note that `ent/entc.go` is ignored using a build tag, and it's executed by the g
 **4\.** In order to execute `gqlgen` through `go generate`, we create a new `generate.go` file (in the root
 of the project) with the following:
 
-```go
+```go title="generate.go"
 package todo
 
 //go:generate go run github.com/99designs/gqlgen
@@ -205,7 +205,7 @@ go generate ./...
 **5\.** `gqlgen` allows changing the generated `Resolver` and add additional dependencies to it. Let's add
 the `ent.Client` as a dependency by pasting the following in `resolver.go`:
 
-```go
+```go title="resolver.go"
 package todo
 
 import (
@@ -229,7 +229,7 @@ func NewSchema(client *ent.Client) graphql.ExecutableSchema {
 
 We create a new directory `cmd/todo` and a `main.go` file with the following code to create the GraphQL server:
 
-```go
+```go title="cmd/todo/main.go"
 package main
 
 import (
@@ -293,7 +293,7 @@ example repository.
 If we try to query our todo list, we'll get an error as the resolver method is not yet implemented. 
 Let's implement the resolver by replacing the `Todos` implementation in the query resolver:
 
-```diff
+```diff title="todo.resolvers.go"
 func (r *queryResolver) Todos(ctx context.Context) ([]*ent.Todo, error) {
 -	panic(fmt.Errorf("not implemented"))
 +	return r.client.Todo.Query().All(ctx)
@@ -317,7 +317,7 @@ query AllTodos {
 Same as before, if we try to create a todo item in GraphQL, we'll get an error as the resolver is not yet implemented.
 Let's implement the resolver by changing the `CreateTodo` implementation in the mutation resolver:
 
-```go
+```go title="todo.resolvers.go"
 func (r *mutationResolver) CreateTodo(ctx context.Context, todo TodoInput) (*ent.Todo, error) {
 	return r.client.Todo.Create().
 		SetText(todo.Text).