Update production-notes.txt

Comments on readahead (i.e. the "TODO update" and such after the "..") were throwing off the formatting and causing those two bullet points to drop to a lower level bullet.  It was confusing, since they are not sub bullets for NUMA...

Signed-off-by: kay <kay.kim@10gen.com>
fix typo in source/reference/operator/query/text.txt
DOCS-3030 add info for downgrade auth model for sharded clusters
DOCS-2502 configuration file options