message: remove unnecessary lookbehind and comment emoticon regex
diff: @@ -47,7 +47,8 @@ import AutocompleteWrapperModel from "../../../editor/autocomplete";
  import DocumentPosition from "../../../editor/position";
  import {ICompletion} from "../../../autocomplete/Autocompleter";
  -const REGEX_EMOTICON_WHITESPACE = new RegExp('(?:^|\\s|(?<=^\\+))(' + EMOTICON_REGEX.source + ')\\s$');
  +// matches emoticons which follow the start of a line, whitespace, or a plus at the start of a line
  +const REGEX_EMOTICON_WHITESPACE = new RegExp('(?:^|\\s|^\\+)(' + EMOTICON_REGEX.source + ')\\s$');
  const IS_MAC = navigator.platform.indexOf("Mac") !== -1;
  