title: Change the multi-line comment characters in Xtext
body: <p>I want a Xtext grammar that allows me to write MIME media types this way:</p>
  
  <pre><code>mediaType application/atom+xml 
  specURL "http://www.rfc-editor.org/rfc/rfc4287.txt",
  </code></pre>
  
  <p>This is not a problem, but the following is:</p>
  
  <pre><code>mediaType application/* 
  specURL "http://www.iana.org/assignments/media-types/application",
  </code></pre>
  
  <p>You can guess of the troubles ahead with the <code>/*</code> characters that usually define a multi-line comment. The terminal for it is defined in the default Terminals provided by Xtext, more specifically in the ML_COMMENT terminal:</p>
  
  <pre><code>terminal ML_COMMENT : '/*' -&gt; '*/';
  </code></pre>
  
  <p>I customized it by copying the default terminals to a new one of my own, where the ML_COMMENT terminal is defined this way instead:</p>
  
  <pre><code>terminal ML_COMMENT : '"""' -&gt; '"""';
  </code></pre>
  
  <p>This produces a more Pythonistic way to have multi-line comments. It works fine in the generated DSL. But the <code>/*</code> characters still pose problem when I try to define the media type for <code>application/*</code>, as shown above. I get an error message of <em>mismatched input '/*' expecting '}'</em> (the <code>}</code> character would specify the end of the media types listing). </p>
  
  <p>Even more troubling is that the content assist of the Xtext editor still auto-fill an ending <code>*/</code> multi-line comment characters when I type a (supposedly obsolete) <code>/*</code> combo characters. As I overrode the multi-line comment terminal, I am wondering why the auto-complete still flirts with the older ML_COMMENT definition. Do I need to override something else?</p>
  
  <p>Here are some fragments for the media type grammar: </p>
  
  <pre><code>MediaType returns restapi::MediaType:
  {restapi::MediaType}
  'mediaType' name=MediaTypeQualifier ('specURL' specURL=EString)?;
  
  MediaTypeQualifier:
      MediaTypeFragment ('/' MediaTypeFragment)?(';' MediaTypeFragment'='MediaTypeFragment)*; 
  
  MediaTypeFragment:
      (ID ( ('-'|'+'|'.') ID )* ) | '*'
  </code></pre>
  
  <p>I am using Xtext version 2.3.1 within Eclipse 4.2.2. Does anyone have experience with overriding the multi-line comment terminal? Is there something that I missed?</p>