Highlight Xtend rich string comments in compare view

Given is the following Foo.xtend file:

package foo

class Foo {
  /**
   * Javadoc comment
   */
   
  /*
   * Multiline comment
   */
   
   // single line comment
   
   val a = '''
   	line
«««   	rich string comment
   	line
   '''
}

The Xtend rich string comments are not highlighted on the compare view. However, the highlighting of all the other comments (javadoc comment, multiline comment, single line comment) are also working in the compare view.

It would be awesome if the highlighting of the rich string comments should also work on the compare view.

Start with the compare view implementation and trace how Javadoc, multiline, and single-line comments are detected for Foo.xtend. Compare that handling with Xtend rich string comments marked by ««« in the issue example. Done means those rich string comments receive the same highlighting in the compare view without regressing the other comment types.