update docs for schema changes

docs/src/extend/custom-rules.md

@@ -58,7 +58,7 @@ The source file for a rule exports an object with the following properties. Both
 
   **Important:** the `hasSuggestions` property is mandatory for rules that provide suggestions. If this property isn't set to `true`, ESLint will throw an error whenever the rule attempts to produce a suggestion. Omit the `hasSuggestions` property if the rule does not provide suggestions.
 
-* `schema`: (`object | array`) Specifies the [options](#options-schemas) so ESLint can prevent invalid [rule configurations](../use/configure/rules).
+* `schema`: (`object | array | false`) Specifies the [options](#options-schemas) so ESLint can prevent invalid [rule configurations](../use/configure/rules). Mandatory when the rule has options.
 
 * `deprecated`: (`boolean`) Indicates whether the rule has been deprecated.  You may omit the `deprecated` property if the rule has not been deprecated.
 
@@ -480,6 +480,13 @@ The `quotes` rule in this example has one option, `"double"` (the `error` is the
 
 ```js
 module.exports = {
+    meta: {
+        schema: [
+            {
+                enum: ["single", "double", "backtick"]
+            }
+        ]
+    },
     create: function(context) {
         var isDouble = (context.options[0] === "double");
 
@@ -492,6 +499,8 @@ Since `context.options` is just an array, you can use it to determine how many o
 
 When using options, make sure that your rule has some logical defaults in case the options are not provided.
 
+Rules with options must specify a [schema](#options-schemas).
+
 ### Accessing the Source Code
 
 The `SourceCode` object is the main object for getting more information about the source code being linted. You can retrieve the `SourceCode` object at any time by using the `context.sourceCode` property:
@@ -610,9 +619,11 @@ You can also access comments through many of `sourceCode`'s methods using the `i
 
 ### Options Schemas
 
-Rules may specify a `schema` property, which is a [JSON Schema](https://json-schema.org/) format description of a rule's options which will be used by ESLint to validate configuration options and prevent invalid or unexpected inputs before they are passed to the rule in `context.options`.
+Rules with options must specify a `meta.schema` property, which is a [JSON Schema](https://json-schema.org/) format description of a rule's options which will be used by ESLint to validate configuration options and prevent invalid or unexpected inputs before they are passed to the rule in `context.options`.
+
+If your rule has options, it is strongly recommended that you specify a schema for options validation. However, it is possible to opt-out of options validation by setting `schema: false`, but doing so is discouraged as it increases the chance of bugs and mistakes.
 
-Note: Prior to ESLint v9.0.0, rules without a schema are passed their options directly from the config without any validation. In ESLint v9.0.0 and later, rules without schemas will throw errors when options are passed. See the [Require schemas and object-style rules](https://github.com/eslint/rfcs/blob/main/designs/2021-schema-object-rules/README.md) RFC for further details.
+For rules that don't specify a `meta.schema` property, ESLint throws errors when any options are passed. If your rule doesn't have options, do not set `schema: false`, but simply omit the schema property or use `schema: []`, both of which prevent any options from being passed.
 
 When validating a rule's config, there are five steps: