patch 9.2.0371: filetype: ghostty config files are not recognized

Problem:  filetype: ghostty config files are not recognized
Solution: Detect ghostty configuration files as ghostty filetype,
          include a simple ghostty filetype plugin (Bez Hermoso)

closes: #20002

Co-authored-by: Christian Brabandt <cb@256bit.org>
Signed-off-by: Bez Hermoso <me@bez.dev>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/testdir/test_filetype.vim

@@ -327,6 +327,9 @@ def s:GetFilenameChecks(): dict<list<string>>
     gedcom: ['file.ged', 'lltxxxxx.txt', '/tmp/lltmp', '/tmp/lltmp-file', 'any/tmp/lltmp', 'any/tmp/lltmp-file'],
     gel: ['file.gel'],
     gemtext: ['file.gmi', 'file.gemini'],
+    ghostty: ['ghostty/config', 'ghostty/keymaps.ghostty', '/.config/ghostty/config', '/.config/ghostty/keymaps.ghostty',
+              '~/Library/Application Support/com.mitchellh.ghostty/config.ghostty', '~/Library/Application Support/com.mitchellh.ghostty/config',
+              '~/.config/ghostty/themes/Custom Theme', '/usr/share/ghostty/themes/Builtin Theme'],
     gift: ['file.gift'],
     gitattributes: ['file.git/info/attributes', '.gitattributes', '/.config/git/attributes', '/etc/gitattributes', '/usr/local/etc/gitattributes', 'some.git/info/attributes'] + WhenConfigHome('$XDG_CONFIG_HOME/git/attributes'),
     gitcommit: ['COMMIT_EDITMSG', 'MERGE_MSG', 'TAG_EDITMSG', 'NOTES_EDITMSG', 'EDIT_DESCRIPTION'],

src/version.c

@@ -734,6 +734,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    371,
 /**/
     370,
 /**/