tests/test-filelog.py.out

commands: rename clone --uncompressed to --stream and document

--uncompressed isn't a very good name and its description in the
help documentation isn't very useful. We refer to this concept as
"stream clones" in a number of places. I think it makes sense to
change the user-facing argument to use the mode --stream. So this
commit does that.

We keep --uncompressed around for backwards compatibility.

While we're here, we overhaul the help docs for streaming clones
to be somewhat useful.

All tests have been updated to reflect the new preferred --stream
argument. A test for backwards compatibility of --uncompressed has
been added.

.. bc::

   `hg clone --stream` should now be used instead of --uncompressed.

   --uncompressed is marked as deprecated and is an alias for --stream.
   There is no schedule for elimination of --uncompressed.

Differential Revision: https://phab.mercurial-scm.org/D864

ERROR: FIXME: This is a known failure of filelog.size for data starting with \1\n
OK.