man.vim: set window local options when reusing buffer

This is necessary incase the buffer was previously opened in a different
tab, in which the window options there do not carry over. It is not
explicitly documented in ':help local-options' but that is how it works.

runtime/autoload/man.vim

@@ -59,6 +59,7 @@ function! man#open_page(count, count1, mods, ...) abort
   if a:mods !~# 'tab' && s:find_man()
     if s:manwidth() ==# getbufvar(bufname, 'manwidth')
       silent execute 'buf' bufname
+      call man#set_window_local_options()
       keepjumps 1
       return
     endif
@@ -68,6 +69,7 @@ function! man#open_page(count, count1, mods, ...) abort
   endif
   noautocmd execute a:mods 'split' bufname
   if s:manwidth() ==# get(b:, 'manwidth')
+    call man#set_window_local_options()
     keepjumps 1
     return
   endif
@@ -203,6 +205,15 @@ function! s:manwidth() abort
   return $MANWIDTH
 endfunction
 
+function! man#set_window_local_options() abort
+  setlocal nonumber
+  setlocal norelativenumber
+  setlocal foldcolumn=0
+  setlocal colorcolumn=0
+  setlocal nolist
+  setlocal nofoldenable
+endfunction
+
 function! s:man_args(sect, name) abort
   if empty(a:sect)
     return shellescape(a:name)

runtime/ftplugin/man.vim

@@ -33,12 +33,7 @@ setlocal tabstop=8
 setlocal softtabstop=8
 setlocal shiftwidth=8
 
-setlocal nonumber
-setlocal norelativenumber
-setlocal foldcolumn=0
-setlocal colorcolumn=0
-setlocal nolist
-setlocal nofoldenable
+call man#set_window_local_options()
 
 if !exists('g:no_plugin_maps') && !exists('g:no_man_maps')
   nmap     <silent> <buffer> <C-]>      <Plug>(Man)