Add an option to reject numbers followed by names

[rmosolgo]

Fixes #4871

This option is off by default now but will be on by default in GraphQL-Ruby 3.0. You can opt into the new behavior with:

# app/graphql/my_schema.rb
GraphQL.reject_numbers_followed_by_names = true 

# ... 

And you can check for invalid query strings using the helper:

transformed_query_str = GraphQL::Language.add_space_between_numbers_and_names(query_str) 
if transformed_query_str.equal?(query_str) 
  # The old string was returned, query_str is valid 
  # do nothing 
else 
   # A new, modified query string was returned 
   # Track this occurrence and/or use the transformed string
   BugTracer.report(:invalid_query_string, query_str)
   query_str = transformed_query_str
end 

TODO:

• Improve tests and implementation of string fix method to handle exponent notation
• Also make sure variable definitions are covered, eg query($a: Int = 5$b: Int = 6) { ... }
• I think that variable definitions and values followed by directives are technically legal because the following character is either @ or $, not a name. I did add tests for input object literals, and they were covered by the current implementation.
• Are there other places where client-provided values appear, where there might be a number literal? (see above)
• Add a CI build which runs with GraphQL.reject_numbers_followed_by_names = true