Deleted 4 old and low rated notes

Following were the 4 notes with a rating less than -5 and
are older than 1 year.

These notes represented 0.0% of the 15951 total user notes,
and have now been removed.

Rating | Note
-------+---------------------------------------------------------
   -6  | https://php.net/manual/en/function.rtrim.php#32755
   -6  | https://php.net/manual/en/thread.getcurrentthreadid.php#126995
   -6  | https://php.net/manual/en/function.file-exists.php#57934
   -6  | https://php.net/manual/en/function.rsort.php#13354