[1.7.x] Fixed #22918 -- Fixed SeparateDatabaseAndState crash

Backport of e03b7940e5 from master
Revert "[1.7.x] Undocumented SeparateDatabaseAndState so crash is not RB. Refs #22918"

This reverts commit a7ac5f018726694e3a79180ef97f2813c715fac0.
[1.7.x] Added missing import in docs/ref/signals.txt.

Backport of 4a303341fc from master
[1.7.x] Cleanup run on the 1.7 release notes. Backport of 138e3873a53a4fcd17ddccaa2132ff1af82dc7a6 from master.
[1.7.x] Bump version number for 1.7 release.