Update math rendering limit docs to 1000
What does this MR do and why?
!243169 (merged) raised MathFilter::RENDER_NODES_LIMIT from 50 to 1000, since the filter no longer performs the expensive sibling-node work that originally motivated the low limit. The docs still stated the old 50-node limit in two places.
This MR updates both to reflect the new limit of 1000, and adds a history entry to the instance limits page.
References
Edited by Asherah Connor