Toggle HTML comment on current selection or tag
@param {IEmmetEditor} editor
@return {Boolean} Returns <code>true</code> if comment was toggled
function toggleHTMLComment(editor) {
		/** @type Range */
		var range = require('range').create(editor.getSelectionRange());
		var info = require('editorUtils').outputInfo(editor);
			
		if (!range.length()) {
			// no selection, find matching tag
			var tag = require('htmlMatcher').tag(info.content, editor.getCaretPos());
			if (tag) { // found pair
				range = tag.outerRange;
			}
		}
		
		return genericCommentToggle(editor, '<!--', '-->', range);
	}