cli: deprecate --record-and-pipe

[bastimeyer]

1. cli: deprecate --record-and-pipe
   • Deprecate --record-and-pipe in favor of --stdout --record=FILENAME
   • Update argparse help texts
   • Update and rearrange create_output() tests
2. cli: refactor check_file_output()
   Change return type to pathlib.Path, so that FileOutput objects are only initialized in create_output()
3. cli: disallow --output=... --stdout
4. docs: add -R/--record-and-pipe deprecation

---

--record-and-pipe was added in #2152 (1.0.0 release).

See #6192 (comment) for why I'm deprecating --record-and-pipe now.

This PR also disallows --output=... --stdout, rather than ignoring the --stdout argument when --output is set, as they are mutually exclusive arguments. Well, unless we change the behavior of --player and --output in the future, and make --output behave like --record (and then remove --record), as mentioned in the comment linked above. Different topic though...

---

--record-and-pipe=file (deprecated)

$ streamlink -l warning --record-and-pipe=/dev/null youtube.com/@hospitalrecords/live best | mpv -
[file] Reading from stdin...
[warnings][streamlinkdeprecation] -R/--record-and-pipe=... has been deprecated in favor of --stdout --record=...
 (+) Video --vid=1 (h264 1920x1080 30.000fps)
 (+) Audio --aid=1 (aac 2ch 44100Hz)
Using hardware decoding (vaapi).
AO: [pipewire] 44100Hz stereo 2ch floatp
VO: [gpu] 1920x1080 vaapi[nv12]
[download] Written 2.65 MiB to /dev/null (1s)

--stdout --record=file (now explicitly allowed)

$ streamlink -l warning --stdout --record=/dev/null youtube.com/@hospitalrecords/live best | mpv -
[file] Reading from stdin...
 (+) Video --vid=1 (h264 1920x1080 30.000fps)
 (+) Audio --aid=1 (aac 2ch 44100Hz)
Using hardware decoding (vaapi).
AO: [pipewire] 44100Hz stereo 2ch floatp
VO: [gpu] 1920x1080 vaapi[nv12]
[download] Written 2.29 MiB to /dev/null (0s)

--stdout --record=- (special case is handled correctly)

$ streamlink -l warning --stdout --record=- youtube.com/@hospitalrecords/live best | mpv -
[file] Reading from stdin...
 (+) Video --vid=1 (h264 1920x1080 30.000fps)
 (+) Audio --aid=1 (aac 2ch 44100Hz)
Using hardware decoding (vaapi).
AO: [pipewire] 44100Hz stereo 2ch floatp
VO: [gpu] 1920x1080 vaapi[nv12]

--stdout --output=file (now disallowed)

$ streamlink -l warning --stdout --output=/dev/null youtube.com/@hospitalrecords/live best | mpv -
[file] Reading from stdin...
error: The -o/--output argument is incompatible with -O/--stdout
Failed to recognize file format.
Exiting... (Errors when loading file)

[bastimeyer]

https://streamlink--6194.org.readthedocs.build/cli.html#file-output-options