config: add alias from `hg help rhg` to `hg help rust` This will make using `rhg` more user-friendly and features more discoverable.

rhg: add `config.rhg` helptext This will make using `rhg` more user-friendly and features more discoverable.

config: fix indentation of some`share-safe` options This makes the output much more readable.

perf-unbundle: do a quick and dirty fix to make it run on more commit Without this change, the perf commands fails within the f67741e8264b::18415fc918a1 range (boundary excluded). Check inline comment for details. With this fix, the command is able to run on this range, with a slightly different behavior (as no revset is "uninlined"). However this is still much better than not being able to run anything in this range. Especially because that range do see some performance regression for unbundle.