Merge remote-tracking branch 'remotes/pmaydell/tags/pull-docs-20190617' into staging

docs infrastructure queue:
 * fix some minor syntax issues in docs/specs/index.rst
 * build and install the 'specs' manual, since it now has some content
 * delete the "QEMU compared to other emulators" section of the docs
 * Convert "translator internals" docs to RST, move to devel manual

# gpg: Signature made Mon 17 Jun 2019 15:56:07 BST
# gpg:                using RSA key E1A5C593CD419DE28E8315CF3C2525ED14360CDE
# gpg:                issuer "peter.maydell@linaro.org"
# gpg: Good signature from "Peter Maydell <peter.maydell@linaro.org>" [ultimate]
# gpg:                 aka "Peter Maydell <pmaydell@gmail.com>" [ultimate]
# gpg:                 aka "Peter Maydell <pmaydell@chiark.greenend.org.uk>" [ultimate]
# Primary key fingerprint: E1A5 C593 CD41 9DE2 8E83  15CF 3C25 25ED 1436 0CDE

* remotes/pmaydell/tags/pull-docs-20190617:
  docs: Build and install specs manual
  docs/specs/index.rst: Fix minor syntax issues
  qemu-tech.texi: Remove "QEMU compared to other emulators" section
  Convert "translator internals" docs to RST, move to devel manual

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