Fix broken markdown in docs (#306).

lib/src/rules/super_goes_last.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 linter.src.rules.super_goes_last;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:linter/src/linter.dart';
 
 const desc =
     'Place the super() call last in a constructor initialization list.';
 
 const details = '''
-From the [style guide] (https://www.dartlang.org/articles/style-guide/):
+From the [style guide](https://www.dartlang.org/articles/style-guide/):
 
 **DO** place the `super()` call last in a constructor initialization list.
 
 Field initializers are evaluated in the order that they appear in the 
 constructor initialization list. If you place a `super()` call in the 
 middle of an initializer list, the superclass's initializers will be evaluated 
 right then before evaluating the rest of the subclass's initializers.
 
 What it doesn't mean is that the superclass's constructor body will be executed 
 then. That always happens after all initializers are run regardless of where 
@@ skipping 42 matching lines @@
     var last = node.initializers.length - 1;
 
     for (int i = 0; i <= last; ++i) {
       var init = node.initializers[i];
       if (init is SuperConstructorInvocation && i != last) {
         rule.reportLint(init);
       }
     }
   }
 }