atomic: merge (delete & copy) changes from trunk


svn path=; revision=84456
Merge big documentation update from Trunk.

svn path=; revision=84459
Merge config doc and test updates.

svn path=; revision=84462
Merge regex bug fix.
Refs #8569.

svn path=; revision=84463
Thread: merge 84414 to fix #8596.

svn path=; revision=84468