Merge branch 'russell/improve-graphql-toggle-docs' into 'master'

Improve example in GraphQL Style Guide's field toggle example

See merge request gitlab-org/gitlab!70562

doc/development/api_graphql_styleguide.md

@@ -532,7 +532,7 @@ Example:
 ```ruby
 field :foo, GraphQL::Types::String,
       null: true,
-      description: 'Some test field. Will always return `null`' \
+      description: 'Some test field. Returns `null`' \
                    'if `my_feature_flag` feature flag is disabled.'
 
 def foo