Minor: adding cross references for shard tag methods
Minor: formatting, added comments about types of tag range, typo correction
Add todo linking SERVER-6357
checkpoint
migrate 1.4 release notes
migrate 1.2 release notes
edits: additional release notes information
DOCS-1063 version numbers
minor: fixing cross reference
merge: migration release notes
merge: release notes old version migration
merge: DOCS-1063
DOCS-1067 syncdely documentation update
DOCS-1067 clarification of syncdelay
minor: fixing build errors
DOCS-979 updated after finding a comment from Randall

Randall commented in email:

_active is probably more correctly thought of as _started -- things remain active (currently) even when they're yielded. At least in my limited test and understanding of the execution logic. _active only goes back to false during a reset/when the op is done.

I checked in the source and _active will only be set to false
if the op has not started or the op has completed, otherwise it
is always true even if the op has yielded to another op.
merge: DOCS-979
fixing structure of release notes page
minor: fix include statements on sharding include page
Typo, add missing "for"