[linter] Drop unnecessary constant_identifier_names ignore.

THe file `lint_codes.g.dart` no longer needs to ignore the
`constant_identifier_names` lint, because linter diagnostic names now
use camelCase.

Change-Id: I6a6a6964cf7595ffe879e9fd6ac12589cfdfe606
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/445406
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Paul Berry <[email protected]>

Author: stereotype441

pkg/linter/lib/src/lint_codes.g.dart

@@ -7,10 +7,6 @@
 // Instead modify 'pkg/linter/messages.yaml' and run
 // 'dart run pkg/linter/tool/generate_lints.dart' to update.
 
-// We allow some snake_case and SCREAMING_SNAKE_CASE identifiers in generated
-// code, as they match names declared in the source configuration files.
-// ignore_for_file: constant_identifier_names
-
 // Generated comments don't quite align with flutter style.
 // ignore_for_file: flutter_style_todos
 

pkg/linter/tool/generate_lints.dart

@@ -47,10 +47,6 @@ GeneratedFile get generatedCodesFile =>
 // Instead modify 'pkg/linter/messages.yaml' and run
 // 'dart run pkg/linter/tool/generate_lints.dart' to update.
 
-// We allow some snake_case and SCREAMING_SNAKE_CASE identifiers in generated
-// code, as they match names declared in the source configuration files.
-// ignore_for_file: constant_identifier_names
-
 // Generated comments don't quite align with flutter style.
 // ignore_for_file: flutter_style_todos