DOCS-2526: removing duplicated section
DOCS-2410: adding note about multikey indexes and shard keys
DOCS-2533: clarification of sharded cluster restoration
DOCS-2535: edits to index building document to admonish an antipattern
DOCS-2436: adding link to MMS docs
DOCS-2142 fix typos
DOCS-2239 DOCS-2466 changes to privilege actions