Fix lints: unnecessary_brace_in_string_interp

pkg/analysis_server/lib/src/services/refactoring/rename_import.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.refactoring.rename_import;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/services/correction/source_range.dart';
@@ skipping 42 matching lines @@
       PrefixElement prefix = element.prefix;
       SourceEdit edit = null;
       if (newName.isEmpty) {
         int uriEnd = element.uriEnd;
         int prefixEnd = element.prefixOffset + prefix.nameLength;
         SourceRange range = rangeStartEnd(uriEnd, prefixEnd);
         edit = newSourceEdit_range(range, "");
       } else {
         if (prefix == null) {
           SourceRange range = rangeStartLength(element.uriEnd, 0);
-          edit = newSourceEdit_range(range, " as ${newName}");
+          edit = newSourceEdit_range(range, " as $newName");
         } else {
           int offset = element.prefixOffset;
           int length = prefix.nameLength;
           SourceRange range = rangeStartLength(offset, length);
           edit = newSourceEdit_range(range, newName);
         }
       }
       if (edit != null) {
         doSourceChange_addElementEdit(change, element, edit);
       }
@@ skipping 34 matching lines @@
     AstNode node = nodeLocator.searchWithin(unit);
     if (node is SimpleIdentifier) {
       AstNode parent = node.parent;
       if (parent is InterpolationExpression && parent.rightBracket == null) {
         return node;
       }
     }
     return null;
   }
 }