patch 9.1.0393: 'viewdir' not respecting $XDG_CONFIG_HOME

Problem:  'viewdir' not respecting $XDG_CONFIG_HOME
          (Danilo Rezende, after v9.1.327)
Solution: adjust 'viewdir' option when enabling XDG config mode

fixes: #14680
closes: #14708

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index 806f5f0..795a5d0 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -1,4 +1,4 @@
-*options.txt*	For Vim version 9.1.  Last change: 2024 Mar 29
+*options.txt*	For Vim version 9.1.  Last change: 2024 May 02
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -6683,7 +6683,8 @@
 <
 				*'runtimepath'* *'rtp'* *vimfiles*
 'runtimepath' 'rtp'	string	(default:
-					Unix:  "$HOME/.vim,
+					Unix:  "$HOME/.vim or
+						$XDG_CONFIG_HOME/vim,
 						$VIM/vimfiles,
 						$VIMRUNTIME,
 						$VIM/vimfiles/after,
@@ -6735,6 +6736,8 @@
 
 	And any other file searched for with the |:runtime| command.
 
+	For $XDG_CONFIG_HOME see |xdg-base-dir|.
+
 	The defaults for most systems are setup to search five locations:
 	1. In your home directory, for your personal preferences.
 	2. In a system-wide Vim directory, for preferences from the system
@@ -8986,13 +8989,15 @@
 						*'viewdir'* *'vdir'*
 'viewdir' 'vdir'	string	(default for Amiga: "home:vimfiles/view",
 					 for Win32: "$HOME/vimfiles/view",
-					 for Unix: "$HOME/.vim/view",
+					 for Unix: "$HOME/.vim/view" or
+					           "$XDG_CONFIG_HOME/vim/view"
 					 for macOS: "$VIM/vimfiles/view",
 					 for VMS: "sys$login:vimfiles/view")
 			global
 			{not available when compiled without the |+mksession|
 			feature}
 	Name of the directory where to store files for |:mkview|.
+	For $XDG_CONFIG_HOME see |xdg-base-dir|.
 	This option cannot be set from a |modeline| or in the |sandbox|, for
 	security reasons.