Remove more libraries directives from server

pkg/analysis_server/lib/src/provisional/completion/dart/completion_target.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.
 
-library analysis_server.src.provisional.completion.dart.completion_target;
-
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/generated/utilities_dart.dart';
 
 int _computeArgIndex(AstNode containingNode, Object entity) {
   var argList = containingNode;
   if (argList is NamedExpression) {
     entity = argList;
@@ skipping 431 matching lines @@
               orElse: () => null);
           paramType = param?.type;
         }
       } else {
         paramType = param.type;
       }
     }
     return paramType is FunctionType || paramType is FunctionTypeAlias;
   }
 }