Revert "Move the linter core to the analyzer package"

pkg/analysis_server/lib/src/services/linter/linter.dart

 // Copyright (c) 2014, 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.
 
 library services.src.linter;
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/plugin/options.dart';
-import 'package:analyzer/src/lint/registry.dart';
+import 'package:linter/src/rules.dart';
 import 'package:yaml/yaml.dart';
 
 /**
  * An error code indicating an undefined lint rule.
  *
  * Parameters:
  * 0: the rule name
  */
 const AnalysisOptionsWarningCode UNDEFINED_LINT_WARNING =
     const AnalysisOptionsWarningCode(
@@ skipping 11 matching lines @@
     if (node is YamlMap) {
       var rules = node.nodes[rulesKey];
       validateRules(rules, reporter);
     }
     return errors;
   }
 
   validateRules(dynamic rules, ErrorReporter reporter) {
     if (rules is YamlList) {
       //TODO(pq): migrate this to a proper API once there is one.
-      Iterable<String> registeredLints =
-          Registry.ruleRegistry.map((r) => r.name);
+      Iterable<String> registeredLints = ruleRegistry.map((r) => r.name);
       rules.nodes.forEach((YamlNode ruleNode) {
         Object value = ruleNode.value;
         if (value != null && !registeredLints.contains(value)) {
           reporter.reportErrorForSpan(
               UNDEFINED_LINT_WARNING, ruleNode.span, [value]);
         }
       });
     }
   }
 }