Fix rustdoc (#12777)

* Fix table formatting

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Fix sp-runtime-interface table

Using HTML now since multi-line tables are not a thing and fmt
destroys them.

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* More rustdoc fixes

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Fix tags

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* More fixes...

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Use Bastis patch

Co-authored-by: Bastian Köcher <git@kchr.de>
Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Add more backticks

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* change ci image

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: Bastian Köcher <git@kchr.de>
Co-authored-by: alvicsam <alvicsam@gmail.com>