Merge remote-tracking branch 'remotes/stsquad/tags/pull-testing-updates-250621-1' into staging

A few miscellaneous fixes

  - tweak tcg/kvm based GIC tests
  - add header to MTTCG docs
  - cleanup checkpatch handling
  - GitLab feature and bug request templates
  - symbol resolution helper for plugin API
  - skip hppa/s390x signals test until fixes arrive

# gpg: Signature made Fri 25 Jun 2021 10:10:57 BST
# gpg:                using RSA key 6685AE99E75167BCAFC8DF35FBD0DB095A9E2A44
# gpg: Good signature from "Alex Bennée (Master Work Key) <alex.bennee@linaro.org>" [full]
# Primary key fingerprint: 6685 AE99 E751 67BC AFC8  DF35 FBD0 DB09 5A9E 2A44

* remotes/stsquad/tags/pull-testing-updates-250621-1:
  plugins/api: expose symbol lookup to plugins
  tests/tcg: skip the signals test for hppa/s390x for now
  GitLab: Add "Feature Request" issue template.
  GitLab: Add "Bug" issue reporting template
  scripts/checkpatch: roll diff tweaking into checkpatch itself
  docs/devel: Add a single top-level header to MTTCG's doc
  tests/acceptance: tweak the tcg/kvm tests for virt

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>