vim: Import v9.1.0988

* runtime(java): Quietly opt out for unsupported markdown.vim versions
* runtime(vim): fix failing vim syntax test
* 9.1.0988: Vim9: no error when using uninitialized var in new()
* runtime(doc): update index.txt
* 9.1.0987: filetype: cake files are not recognized
* 9.1.0986: filetype: 'jj' filetype is a bit imprecise
* runtime(jj): Support diffs in jj syntax
* runtime(vim): Update matchit pattern, no Vim9 short names
* 9.1.0985: Vim9: some ex commands can be shortened

Author: github-actions[bot]

gitlog.txt

@@ -1 +1 @@
-* [9.1.0984](https://github.com/vim/vim/commit/663d18d6102f40d14e36096ec590445e61026ed6): exception handling can be improved\n* [runtime(doc): update doc for :horizontal](https://github.com/vim/vim/commit/fd771613b3e59923b1a82a5ed9036c82899d133b)\n* [runtime(doc): update index.txt, windows.txt and version9.txt](https://github.com/vim/vim/commit/0c3e57b403e0e3a1fefca7bbd5ad4cb950eea616)\n* [runtime(doc): Tweak documentation about base64 function](https://github.com/vim/vim/commit/e80f345b5dbc0ef3186d640e3d5adb7fcdfef64c)
+* [runtime(java): Quietly opt out for unsupported markdown.vim versions](https://github.com/vim/vim/commit/cd96075cdee6b606c6e39aa1aed19b7cdc867df8)\n* [runtime(vim): fix failing vim syntax test](https://github.com/vim/vim/commit/6139766e825ca34948223cb4c88d3900b1940a17)\n* [9.1.0988](https://github.com/vim/vim/commit/b04af4cc9636ccbadc625e743a265a394bd48943): Vim9: no error when using uninitialized var in new()\n* [runtime(doc): update index.txt](https://github.com/vim/vim/commit/27f2e473e1d6077264b214e58995001383162705)\n* [9.1.0987](https://github.com/vim/vim/commit/a407573f30a978b3aa61532bbd9b0ae94a87dc32): filetype: cake files are not recognized\n* [9.1.0986](https://github.com/vim/vim/commit/58c44e8833365e1a777330491c2799ae324ed893): filetype: 'jj' filetype is a bit imprecise\n* [runtime(jj): Support diffs in jj syntax](https://github.com/vim/vim/commit/bde76da4d02d93d8ea9e523d1057d59a19de276a)\n* [runtime(vim): Update matchit pattern, no Vim9 short names](https://github.com/vim/vim/commit/fc61cfd60e6d99765d1a68d39d6613e0917c7c56)\n* [9.1.0985](https://github.com/vim/vim/commit/aa979c763da2fa7ede2416a1ab8de7a46d88cd04): Vim9: some ex commands can be shortened