Parse and render rst syntax in :short: statement descriptions in tables

Parse and render rst syntax in :short: statement descriptions in tables

Without this change tables generated by .. namedconf:statementlist::
contained raw text and displayed rst syntax to users.

The raw docutil node returned by rst parser can contain unresolved
references (pending_xref nodes). We just store those nodes and let
Sphinx to resolve them later on.

Beware: This would not work if we injected nodes in later stages of
processing. All unresolved references must be in place before
'doctree-resolved' event is emitted (i.e. before resolve_references() is
called inside Sphinx).

(cherry picked from commit 62f3cf98d37ab629c38333c5fb9313872ac90cf0)