amend option for hg commit is introduced in Mercurial 2.2.
The --amend flag can be used to amend the parent of the working directory
with a new commit that contains the changes in the parent in addition to
those currently reported by "hg status", if there are any. The old commit
is stored in a backup bundle in ".hg/strip-backup" (see "hg help bundle"
and "hg help unbundle" on how to restore it).
Is it possible to support this flag in sourceTree?