rust: remove dead code Differential Revision: https://phab.mercurial-scm.org/D11549

Added signature for changeset 750920b18aaa

Added tag 5.9.2 for changeset 750920b18aaa

rust-revset: support explicit `.` revision This is basically the same thing as not specifying a revision, except this is done in the revset resolution function. This allows calls like `rhg cat some-file -r .` to work without falling back. Differential Revision: https://phab.mercurial-scm.org/D11402

rust-revset: add separate match logic for shortcuts The next change will add a shortcut for the `.` revision. One day we might start matching `tip` and others, so this is an easy refactor. Differential Revision: https://phab.mercurial-scm.org/D11401

rhg: fall back if subrepos are detected We do not handle subrepos yet, the addition of the support for `-r .` will break if we don't fall back. Differential Revision: https://phab.mercurial-scm.org/D11403