idlwave: Comment Indentation

 
 4.1.3 Comment Indentation
 -------------------------
 
 In IDL, lines starting with a ‘;’ are called _comment lines_.  Comment
 lines are indented as follows:
 
 ‘;;;’   The indentation of lines starting with three semicolons remains
         unchanged.
 ‘;;’    Lines starting with two semicolons are indented like the
         surrounding code.
 ‘;’     Lines starting with a single semicolon are indented to a
         minimum column.
 
 The indentation of comments starting in column 0 is never changed.
 
  -- User Option: idlwave-no-change-comment
      The indentation of a comment starting with this regexp will not be
      changed.
 
  -- User Option: idlwave-begin-line-comment
      A comment anchored at the beginning of line.
 
  -- User Option: idlwave-code-comment
      A comment that starts with this regexp is indented as if it is a
      part of IDL code.