man.vim #5249

- fix synopsis highlighting in other locales. Cannot always rely on the first
  line for the section in some locales; instead, use the file path and
  explicitly set b:man_sect to the actual section.
- eliminate separate s:man_args function
- simplify logic: do not reuse buffer content
- introduce b:man_default_sects Fixes #5233
- introduce <Plug>(man_vsplit), <Plug>(man_tab)
- simplify regexps

runtime/ftplugin/c.vim

@@ -55,5 +55,7 @@ if (has("gui_win32") || has("gui_gtk")) && !exists("b:browsefilter")
   endif
 endif
 
+let b:man_default_sects = '3,2'
+
 let &cpo = s:cpo_save
 unlet s:cpo_save