uncommit: move fb-extension to core which uncommits a changeset
uncommit extension in fb-hgext adds a uncommit command which by default
uncommits a changeset and move all the changes to the working directory. If
file names are passed, uncommit moves the changes from those files to the
working directory and left the changeset with remaining committed files.
The uncommit extension in fb-hgext does not creates an empty commit like the one
in evolve extension unless user has specified ui.alllowemptycommit to True.
The test file added is a combination of tests from test-uncommit.t,
test-uncommit-merge.t and test-uncommit-bookmark.t from fb-hgext.
.. feature::
A new uncommit extension which provides `hg uncommit` using which one can
uncommit part or all of the changeset. This command undoes the effect of a
local commit, returning the affected files to their uncommitted state.
Differential Revision: https://phab.mercurial-scm.org/D529