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>

runtime/autoload/dist/ft.vim

@@ -3,7 +3,7 @@ vim9script
 # Vim functions for file type detection
 #
 # Maintainer:		The Vim Project <https://github.com/vim/vim>
-# Last Change:		2026 Apr 15
+# Last Change:		2026 Apr 20
 # Former Maintainer:	Bram Moolenaar <Bram@vim.org>
 
 # These functions are moved here from runtime/filetype.vim to make startup
@@ -3113,7 +3113,9 @@ const ft_from_ext = {
   "bp": "bp",
   # Tiltfile
   "Tiltfile": "tiltfile",
-  "tiltfile": "tiltfile"
+  "tiltfile": "tiltfile",
+  # Ghostty
+  "ghostty": "ghostty",
 }
 # Key: file name (the final path component, excluding the drive and root)
 # Value: filetype

runtime/filetype.vim

@@ -1,7 +1,7 @@
 " Vim support file to detect file types
 "
 " Maintainer:		The Vim Project <https://github.com/vim/vim>
-" Last Change:		2026 Apr 08
+" Last Change:		2026 Apr 20
 " Former Maintainer:	Bram Moolenaar <Bram@vim.org>
 
 " If the filetype can be detected from extension or file name(the final path component),
@@ -1617,6 +1617,10 @@ au BufNewFile,BufRead *.txt
 	\|   setf text
 	\| endif
 
+" Ghostty configuration
+au BufNewFile,BufRead */ghostty/config                      setf ghostty
+au BufNewFile,BufRead */ghostty/themes/*                    call s:StarSetf('ghostty')
+au BufNewFile,BufRead */com.mitchellh.ghostty/config        setf ghostty
 
 
 " Generic log file

runtime/ftplugin/ghostty.vim

@@ -0,0 +1,10 @@
+" Vim filetype plugin file
+" Language: ghostty
+
+" Quit if a ftplugin file was already loaded
+if exists("b:did_ftplugin")
+  finish
+endif
+
+" Use the cfg plugin, it's similar enough.
+runtime! ftplugin/cfg.vim