DOCSP-15083 updates file limit rec to 128000

Author: jmd-mongo

source/reference/ulimit.txt

@@ -230,7 +230,7 @@ the following thresholds and settings are particularly important for
 - ``-t`` (cpu time): ``unlimited``
 - ``-v`` (virtual memory): ``unlimited`` [#memory-size]_
 - ``-l`` (locked-in-memory size): ``unlimited``
-- ``-n`` (open files): ``64000``
+- ``-n`` (open files): ``128000``
 - ``-m`` (memory size): ``unlimited`` [#memory-size]_ [#rss-linux]_
 - ``-u`` (processes/threads): ``64000``