bashcompletion: show available command-line switches for aliases When auto-completing hg commands, aliases are listed, but not the available switches for an alias, because `HGPLAIN=1` filters these out. Add a `HGPLAINEXCEPT=alias` exception to resolve this. We make heavy use of aliases that drive hg log with custom revsets, sorting and the -G switch, but want our users to be able to auto-complete any additional command-line switches.