patch 9.1.1764: filetype: CODEOWNERS file not recognized

Problem:  filetype: CODEOWNERS file not recognized
Solution: Detect CODEOWNERS file as codeowners filetype, include a
          syntax and filetype plugin (Jon Parise).

CODEOWNERS files define code ownership rules for GitHub-hosted (and
other) repositories. The syntax is similar to 'gitignore' files but
differs in enough ways to warrant its own filetype.

References:
- https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/about-code-owners

closes: #18299

Signed-off-by: Jon Parise <jon@indelible.org>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/testdir/test_filetype.vim

@@ -189,6 +189,7 @@ def s:GetFilenameChecks(): dict<list<string>>
     cmusrc: ['any/.cmus/autosave', 'any/.cmus/rc', 'any/.cmus/command-history', 'any/.cmus/file.theme', 'any/cmus/rc', 'any/cmus/file.theme', '/.cmus/autosave', '/.cmus/command-history', '/.cmus/file.theme', '/.cmus/rc', '/cmus/file.theme', '/cmus/rc'],
     cobol: ['file.cbl', 'file.cob'],
     coco: ['file.atg'],
+    codeowners: ['CODEOWNERS'],
     conaryrecipe: ['file.recipe'],
     conf: ['auto.master', 'file.conf', 'texdoc.cnf', '.x11vncrc', '.chktexrc', '.ripgreprc', 'ripgreprc', 'file.ctags'],
     config: ['/etc/hostname.file', 'any/etc/hostname.file', 'configure.in', 'configure.ac', 'file.at', 'aclocal.m4'],

src/version.c

@@ -724,6 +724,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1764,
 /**/
     1763,
 /**/