[cleanup] Misc (#11216)

- Add Python 3.13 to CI, finalize 3.13 support
- Remove Python 3.8 from CI in preparation for removing 3.8 support
- Document that PyPy3.8 and PyPy3.9 are no longer supported
- Usual documentation fixes and code cleanup

Closes #8248, Closes #11146, Closes #11149, Closes #11211
Authored by: Grub4K, grqz, DTrombett, KarboniteKream, bashonly, mikkovedru, seproDev

Co-authored-by: N/Ame <173015200+grqz@users.noreply.github.com>
Co-authored-by: DTrombett <d@trombett.org>
Co-authored-by: =?UTF-8?q?Klemen=20Ko=C5=A1ir?= <klemen.kosir@kream.io>
Co-authored-by: bashonly <88596187+bashonly@users.noreply.github.com>
Co-authored-by: Mikko Vedru <mikko.vedru@gmail.com>
Co-authored-by: sepro <sepro@sepr0.com>

yt_dlp/extractor/youtube.py

@@ -7792,9 +7792,9 @@ class YoutubeTruncatedURLIE(YoutubeBaseInfoExtractor):
         raise ExtractorError(
             'Did you forget to quote the URL? Remember that & is a meta '
             'character in most shells, so you want to put the URL in quotes, '
-            'like  youtube-dl '
+            'like  yt-dlp '
             '"https://www.youtube.com/watch?feature=foo&v=BaW_jenozKc" '
-            ' or simply  youtube-dl BaW_jenozKc  .',
+            ' or simply  yt-dlp BaW_jenozKc  .',
             expected=True)