Fix lints: unnecessary_brace_in_string_interp

pkg/analysis_server/lib/src/services/refactoring/inline_method.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.inline_method;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
 import 'package:analysis_server/src/services/correction/source_range.dart';
@@ skipping 505 matching lines @@
         SourceEdit edit = newSourceEdit_range(range, source);
         _addRefEdit(edit);
       }
       // replace invocation with return expression
       if (ref._methodExpressionPart != null) {
         // prepare expression source for invocation
         String source = _getMethodSourceForInvocation(status,
             ref._methodExpressionPart, _refUtils, usage, target, arguments);
         if (getExpressionPrecedence(ref._methodExpression) <
             getExpressionParentPrecedence(usage)) {
-          source = "(${source})";
+          source = "($source)";
         }
         // do replace
         SourceRange methodUsageRange = rangeNode(usage);
         SourceEdit edit = newSourceEdit_range(methodUsageRange, source);
         _addRefEdit(edit);
       } else {
         SourceEdit edit = newSourceEdit_range(_refLineRange, "");
         _addRefEdit(edit);
       }
       return;
@@ skipping 276 matching lines @@
   }
 
   void _addVariable(SimpleIdentifier node) {
     VariableElement variableElement = getLocalVariableElement(node);
     if (variableElement != null) {
       SourceRange nodeRange = rangeNode(node);
       result.addVariable(variableElement, nodeRange);
     }
   }
 }