[analyzer][docs][NFC] Fix some broken links and some cosmetic changes

- We should report bugs to the GitHub Issues
- We should advocate using Discourse instead of the superseded cfe-dev
  mailing list.

There are a couple of other cosmetic changes such as preferring `using`
instead of `typedef` and quoting the `-analyze-function` parameter's
payload for escaping the braces.

Thanks @loic-joly-sonarsource for reporting this on Discord!

Reviewed By: NoQ, Szelethus

Differential Revision: https://reviews.llvm.org/D119245