runtime(man): honor cmd modifiers before `g:ft_man_open_mode`

Give priority to (placement) command modifiers, specifically
`:vertical`, `:horizontal` and `:tab`, ahead of `g:ft_man_open_mode`,
so that if the user says e.g. `:vert Man`, Vim does the expected thing.

closes: #15117

Signed-off-by: Ivan Shapovalov <intelfx@intelfx.name>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/autoload/dist/man.vim b/runtime/autoload/dist/man.vim
index 708e106..d9dbaf4 100644
--- a/runtime/autoload/dist/man.vim
+++ b/runtime/autoload/dist/man.vim
@@ -4,6 +4,7 @@
 " Maintainer:	SungHyun Nam <goweol@gmail.com>
 " Autoload Split: Bram Moolenaar
 " Last Change: 	2024 Jan 17 (make it work on AIX, see #13847)
+" 		2024 Jul 06 (honor command modifiers, #15117)
 
 let s:cpo_save = &cpo
 set cpo-=C
@@ -165,7 +166,9 @@
       endwhile
     endif
     if &filetype != "man"
-      if exists("g:ft_man_open_mode")
+      if a:cmdmods =~ '\<\(tab\|vertical\|horizontal\)\>'
+	let open_cmd = a:cmdmods . ' split'
+      elseif exists("g:ft_man_open_mode")
         if g:ft_man_open_mode == 'vert'
 	  let open_cmd = 'vsplit'
         elseif g:ft_man_open_mode == 'tab'
@@ -174,7 +177,7 @@
 	  let open_cmd = 'split'
         endif
       else
-	let open_cmd = a:cmdmods . ' split'
+	let open_cmd = 'split'
       endif
     endif
   endif
diff --git a/runtime/ftplugin/man.vim b/runtime/ftplugin/man.vim
index 87484bf..f0723ef 100644
--- a/runtime/ftplugin/man.vim
+++ b/runtime/ftplugin/man.vim
@@ -4,6 +4,7 @@
 " Maintainer:	SungHyun Nam <goweol@gmail.com>
 " Autoload Split: Bram Moolenaar
 " Last Change:	2024 Jun 06 (disabled the q mapping, #8210)
+" 		2024 Jul 06 (use nnoremap, #15130)
 
 " To make the ":Man" command available before editing a manual page, source
 " this script from your startup vimrc file.