code: public MentionsEditable trim() {
          // Delete beginning spaces
          while (length() > 0 && Character.isWhitespace(charAt(0))) {
              delete(0, 1);
          }
          // Delete ending spaces
          int len = length();
          while (len > 0 && Character.isWhitespace(charAt(len - 1))) {
              delete(len - 1, len);
              len--;
          }
          return new MentionsEditable(this, 0, length());
      }
docs: Implementation of {@link String#trim()} for an {@link Editable}.
  
  @return a new {@link MentionsEditable} with whitespace characters removed from the beginning and the end