Deleted 6 old and low rated notes

Following were the 6 notes with a rating less than -5 and
are older than 1 year.

These notes represented 0.0% of the 15873 total user notes,
and have now been removed.

Rating | Note
-------+---------------------------------------------------------
   -6  | https://php.net/manual/en/ini.core.php#124935
   -6  | https://php.net/manual/en/security.hiding.php#41458
   -6  | https://php.net/manual/en/language.types.float.php#128781
   -6  | https://php.net/manual/en/function.substr-replace.php#112448
   -6  | https://php.net/manual/en/function.substr-replace.php#25843
   -6  | https://php.net/manual/en/function.openssl-pkey-get-public.php#83670