[analyzer][NFC] Make CheckerDocumentation checker in-sync with actual checker callbacks (#83973)

In PR #83677 I was surprised to see that outdated checker callback
signatures are a problem. It turns out, we need the `registerChecker...`
function to invoke the `Mgr.registerChecker<>()` which would instantiate
the `_register` calls, that would take the address of the defined
checker callbacks. Consequently, if the expected signatures mismatch, it
won't compile from now on, so we have static guarantee that this issue
never pops up again.

Given we need the `register` call, at this point we could just hook this
checker into the `debug` package and make it never registered. It
shouldn't hurt anyone :)