Work around hostile ftplugin/man.vim

References: https://github.com/neovim/neovim/issues/15487

autoload/fugitive.vim

@@ -2961,6 +2961,9 @@ function! s:TempReadPost(file) abort
       call fugitive#MapJumps()
     endif
     if has_key(dict, 'filetype')
+      if dict.filetype ==# 'man' && has('nvim')
+        let b:man_sect = matchstr(getline(1), '^\w\+(\zs\d\+\ze)')
+      endif
       let &l:filetype = dict.filetype
     endif
     setlocal foldmarker=<<<<<<<<,>>>>>>>>