Merge remote-tracking branch 'remotes/armbru/tags/pull-misc-2020-12-10' into staging

Merge remote-tracking branch 'remotes/armbru/tags/pull-misc-2020-12-10' into staging

Miscellaneous patches for 2020-12-10

# gpg: Signature made Thu 10 Dec 2020 16:17:43 GMT
# gpg:                using RSA key 354BC8B3D7EB2A6B68674E5F3870B400EB918653
# gpg:                issuer "armbru@redhat.com"
# gpg: Good signature from "Markus Armbruster <armbru@redhat.com>" [full]
# gpg:                 aka "Markus Armbruster <armbru@pond.sub.org>" [full]
# Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867  4E5F 3870 B400 EB91 8653

* remotes/armbru/tags/pull-misc-2020-12-10:
  docs/devel/writing-qmp-commands.txt: Fix docs
  qapi: Normalize version references x.y.0 to just x.y
  Tweak a few "Parameter 'NAME' expects THING" error message
  qom: Improve {qom,device}-list-properties error messages
  qga: Tweak a guest-shutdown error message
  qga: Replace an unreachable error by abort()
  ui: Tweak a client_migrate_info error message
  ui: Improve a client_migrate_info error message
  ui: Improve some set_passwd, expire_password error messages
  block: Improve some block-commit, block-stream error messages
  qerror: Eliminate QERR_ macros used in just one place
  qerror: Drop unused QERR_ macros
  Clean up includes

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