QAPI patches for 2020-02-15

# gpg: Signature made Sat 15 Feb 2020 10:44:28 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-qapi-2020-02-15:
  qapi: Delete all the "foo: dropped in n.n" notes
  qapi/migration.json: Replace _this_ with *this*
  qapi: Add blank lines before bulleted lists
  qapi: Use explicit bulleted lists
  qapi/ui.json: Avoid `...' Texinfo style quoting
  qapi/ui.json: Put input-send-event body text in the right place
  qapi: Remove hardcoded tabs
  qapi: Fix indent level on doc comments in json files
  qapi: Fix incorrect "Not documented" claims in QMP documentation
  qapi/block-core.json: Use literal block for ascii art
  qga/qapi-schema.json: minor format fixups for rST
  qga/qapi-schema.json: Fix indent level on doc comments
  qga/qapi-schema.json: Fix missing '-' in GuestDiskBusType doc comment
  Makefile: Fix typo in dependency list for interop manpages
  configure: Check that sphinx-build is using Python 3
  configure: Pick sphinx-build-3 when available
  configure: Allow user to specify sphinx-build binary
  qapi: Expand documentation for LostTickPolicy

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