Fix hints by removing deprecation from used methods

pkg/analyzer/lib/src/lint/util.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:io';
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/src/dart/ast/token.dart';
 import 'package:analyzer/src/dart/scanner/reader.dart';
@@ skipping 32 matching lines @@
   path = path.replaceAll('/', '.');
   // Add separator if needed.
   if (path.isNotEmpty) {
     path = '.$path';
   }
 
   return '$packageName$path';
 }
 
 /// Returns `true` if this [fileName] is a Dart file.
-@deprecated // Never intended for public use.
 bool isDartFileName(String fileName) => fileName.endsWith('.dart');
 
 /// Returns `true` if this [name] is a legal Dart identifier.
 @deprecated // Never intended for public use.
 bool isIdentifier(String name) => _identifier.hasMatch(name);
 
 /// Returns `true` of the given [name] is composed only of `_`s.
 @deprecated // Never intended for public use.
 bool isJustUnderscores(String name) => _underscores.hasMatch(name);
 
 /// Returns `true` if this [id] is `lowerCamelCase`.
 @deprecated // Never intended for public use.
 bool isLowerCamelCase(String id) =>
     id.length == 1 && isUpperCase(id.codeUnitAt(0)) ||
     id == '_' ||
     _lowerCamelCase.hasMatch(id);
 
 /// Returns `true` if this [id] is `lower_camel_case_with_underscores`.
 @deprecated // Never intended for public use.
 bool isLowerCaseUnderScore(String id) => _lowerCaseUnderScore.hasMatch(id);
 
 /// Returns `true` if this [id] is `lower_camel_case_with_underscores_or.dots`.
 @deprecated // Never intended for public use.
 bool isLowerCaseUnderScoreWithDots(String id) =>
     _lowerCaseUnderScoreWithDots.hasMatch(id);
 
 /// Returns `true` if this [fileName] is a Pubspec file.
-@deprecated // Never intended for public use.
 bool isPubspecFileName(String fileName) => _pubspec.hasMatch(fileName);
 
 /// Returns `true` if the given code unit [c] is upper case.
 @deprecated // Never intended for public use.
 bool isUpperCase(int c) => c >= 0x40 && c <= 0x5A;
 
 class Spelunker {
   final String path;
   final IOSink sink;
   Spelunker(this.path, {IOSink sink}) : this.sink = sink ?? stdout;
@@ skipping 79 matching lines @@
 
   write(AstNode node) {
     //EOL comments
     var comments = getPrecedingComments(node.beginToken);
     comments.forEach((c) => sink.writeln('${"  " * indent}$c'));
 
     sink.writeln(
         '${"  " * indent}${asString(node)} ${getTrailingComment(node)}');
   }
 }