Update errors.md for v2.6
SERVER-14302 SERVER-14304 Fix IDHackRunner's use of sharding filter

(backport of 6fe6dee814326ac41f8d626c26bf32763ce73d71)
(cherry picked from commit 3d19c459fe80fb7aa3244174b61994f13f71c21f)
prep 2.6.4-pre-
Merge remote-tracking branch 'upstream/v2.6' into v2.6