fa324a8b15a4ef4138685b3427c895ec14faf3af doc: Rewrite some validation doc as lock annotations (MarcoFalke)
Pull request description:
#13402 added some lock annotations in comments. This pull removes them and adds clang-readable locking annotations instead.
Tree-SHA512: 2d392efa8ac4978830a9df08b2009e69d6f1ac031f62be2275ae8d7c7e483331c7f8d458d865443af907a7af27a592421c6cca6b2df3f2877e0f369b9198f383
Backport of Core PR13481
https://github.com/bitcoin/bitcoin/pull/13481/
Also partial backport of PR14444
https://github.com/bitcoin/bitcoin/pull/14444/
Depends on D4029