bundlespec: make the `stream` case less special
The handling of the stream case seems fragile (does not account for newer parts
and options that will arise) and has special code dedicated to it.
To simplify and strengthen things, we make it use the same mechanism as the other
options. So we make it less special by making it a special value in the common case.
#require emacs
$ emacs -q -no-site-file -batch -l $TESTDIR/../contrib/hg-test-mode.el \
> -f ert-run-tests-batch-and-exit
Running 1 tests (*) (glob)
passed 1/1 hg-test-mode--compilation-mode-support* (glob)
Ran 1 tests, 1 results as expected* (glob)