.hgignore

patchbomb: fix traceback on outgoing when not specifying revisions

A user reported that `hg email -n -o` raised with the following traceback:

```
** unknown exception encountered, please report by visiting
** https://mercurial-scm.org/wiki/BugTracker
** Python 3.8.12 (default, Sep 13 2021, 22:12:54) [GCC 7.5.0]
** Mercurial Distributed SCM (version 5.9.1)
** Extensions loaded: patchbomb
Traceback (most recent call last):
  File "/usr/pkg/bin/hg", line 61, in <module>
    dispatch.run()
  File "/usr/pkg/lib/python3.8/site-packages/mercurial/dispatch.py", line 144, in run
    status = dispatch(req)
  File "/usr/pkg/lib/python3.8/site-packages/mercurial/dispatch.py", line 250, in dispatch
    status = _rundispatch(req)
  File "/usr/pkg/lib/python3.8/site-packages/mercurial/dispatch.py", line 294, in _rundispatch
    ret = _runcatch(req) or 0
  File "/usr/pkg/lib/python3.8/site-packages/mercurial/dispatch.py", line 470, in _runcatch
    return _callcatch(ui, _runcatchfunc)
  File "/usr/pkg/lib/python3.8/site-packages/mercurial/dispatch.py", line 480, in _callcatch
    return scmutil.callcatch(ui, func)
  File "/usr/pkg/lib/python3.8/site-packages/mercurial/scmutil.py", line 153, in callcatch
    return func()
  File "/usr/pkg/lib/python3.8/site-packages/mercurial/dispatch.py", line 460, in _runcatchfunc
    return _dispatch(req)
  File "/usr/pkg/lib/python3.8/site-packages/mercurial/dispatch.py", line 1273, in _dispatch
    return runcommand(
  File "/usr/pkg/lib/python3.8/site-packages/mercurial/dispatch.py", line 918, in runcommand
    ret = _runcommand(ui, options, cmd, d)
  File "/usr/pkg/lib/python3.8/site-packages/mercurial/dispatch.py", line 1285, in _runcommand
    return cmdfunc()
  File "/usr/pkg/lib/python3.8/site-packages/mercurial/dispatch.py", line 1271, in <lambda>
    d = lambda: util.checksignature(func)(ui, *args, **strcmdopt)
  File "/usr/pkg/lib/python3.8/site-packages/mercurial/util.py", line 1886, in check
    return func(*args, **kwargs)
  File "/usr/pkg/lib/python3.8/site-packages/hgext/patchbomb.py", line 817, in email
    revs = _getoutgoing(repo, dest, revs)
  File "/usr/pkg/lib/python3.8/site-packages/hgext/patchbomb.py", line 537, in _getoutgoing
    safe_paths = [urlutil.hidepassword(p.rawloc) for p in paths]
  File "/usr/pkg/lib/python3.8/site-packages/hgext/patchbomb.py", line 537, in <listcomp>
    safe_paths = [urlutil.hidepassword(p.rawloc) for p in paths]
  File "/usr/pkg/lib/python3.8/site-packages/mercurial/utils/urlutil.py", line 501, in get_push_paths
    msg %= dest
TypeError: %b requires a bytes-like object, or an object that implements __bytes__, not 'NoneType'
```

This is due to patchbomb passing `[None]` in the `dests` parameter of the
multi-paths outgoing function, we fix this in this change and add a
non-regression test.

Differential Revision: https://phab.mercurial-scm.org/D11456

syntax: glob

*.elc
*.tmp
*.orig
*.rej
*~
*.mergebackup
*.o
*.so
*.dll
*.exe
*.pyd
*.pyc
*.pyo
*$py.class
*.swp
*.prof
*.zip
\#*\#
.\#*
tests/artifacts/cache/big-file-churn.hg
tests/.coverage*
tests/.testtimes*
tests/.hypothesis
tests/hypothesis-generated
tests/annotated
tests/exceptions
tests/python3
tests/*.err
tests/htmlcov
build
contrib/chg/chg
contrib/hgsh/hgsh
contrib/vagrant/.vagrant
dist
packages
doc/common.txt
doc/*.[0-9]
doc/*.[0-9].txt
doc/*.[0-9].gendoc.txt
doc/*.[0-9].{x,ht}ml
MANIFEST
MANIFEST.in
patches
mercurial/__modulepolicy__.py
mercurial/__version__.py
mercurial/hgpythonlib.h
mercurial.egg-info
.DS_Store
tags
cscope.*
.vscode/*
.idea/*
.asv/*
.pytype/*
.mypy_cache
i18n/hg.pot
locale/*/LC_MESSAGES/hg.mo
hgext/__index__.py

rust/target/
rust/*/target/

# Generated wheels
wheelhouse/

syntax: rootglob
# See Profiling in rust/README.rst
.cargo/config

syntax: regexp
^\.pc/
^\.(pydev)?project

# hackable windows distribution additions
^hg-python
^hg.py$