vim-patch:9.1.0278: filetype: zathurarc files not recognized

Problem:  filetype: zathurarc files not recognized
Solution: Detect '.zathurarc' files as zathurarc filetype,
          add zathurarc filetype (Wu, Zhenyu)

closes: vim/vim#14380

72d81a66ed

Co-authored-by: Wu, Zhenyu <wuzhenyu@ustc.edu>

runtime/ftplugin/zathurarc.vim

@@ -0,0 +1,22 @@
+" Vim filetype plugin file
+" Language:             Zathurarc
+" Maintainer:           Wu, Zhenyu <wuzhenyu@ustc.edu>
+" Documentation:        https://pwmt.org/projects/zathura/documentation/
+" Upstream:             https://github.com/Freed-Wu/zathurarc.vim
+" Latest Revision:      2024-04-02
+
+if exists('b:did_ftplugin')
+  finish
+endif
+let b:did_ftplugin = 1
+
+let s:save_cpoptions = &cpoptions
+set cpoptions&vim
+
+let b:undo_ftplugin = 'setlocal comments< commentstring< include<'
+setlocal comments=:#
+setlocal commentstring=#\ %s
+setlocal include=^\sinclude
+
+let &cpoptions = s:save_cpoptions
+unlet s:save_cpoptions