test release: 5.9.0.4-test (will be 5.9.1)

hello,

i've tagged 5.9.0.4-test and uploaded the artefacts to:

  https://sourceforge.net/projects/zsh/files/zsh-test/5.9.0.4-test/

if you have time, please test and report any issues

note: this is a test release for what will become 5.9.1, *not* for the
still-in-development 5.10*

although there are more changes than usual due to the recent lack of
releases, 5.9.1 is still just a maintenance update. it contains no new
functionality except the following:

- completion functions have been updated
- the zsh/pcre module has been migrated to pcre2
- posix real-time signals are supported where available
- the kill built-in gained the -L and -q options

see README and NEWS for more details

dana

* the previous two test releases, 5.9.0.2-test and 5.9.0.3-test, *were*
  for 5.10. this confusing sequence is due to inadequacies in the
  test-release process which will be corrected for next time. it won't
  affect the final release of either version