patch 8.2.0320: no Haiku support

Problem:    No Haiku support.
Solution:   Add support for Haiku. (Emir Sari, closes #5605)
diff --git a/runtime/doc/starting.txt b/runtime/doc/starting.txt
index b9a2370..f437c0e 100644
--- a/runtime/doc/starting.txt
+++ b/runtime/doc/starting.txt
@@ -790,6 +790,7 @@
 				or $VIM/_vimrc
 		Amiga		s:.vimrc, home:.vimrc, home:vimfiles:vimrc
 				or $VIM/.vimrc
+		Haiku		$HOME/config/settings/vim/vimrc
 
 	The files are searched in the order specified above and only the first
 	one that is found is read.
@@ -835,6 +836,8 @@
 		    "$HOME/_vimrc"	   (for Win32) (*)
 		    "$HOME/vimfiles/vimrc" (for Win32) (*)
 		    "$VIM/_vimrc"	   (for Win32) (*)
+		    "$HOME/config/settings/vim/vimrc"	(for Haiku) (*)
+
 		Note: For Unix and Amiga, when ".vimrc" does not exist,
 		"_vimrc" is also tried, in case an MS-DOS compatible file
 		system is used.  For MS-Windows ".vimrc" is checked after
@@ -950,6 +953,8 @@
 	~/.vimrc	(Unix)
 	s:.vimrc	(Amiga)
 	$VIM\_vimrc	(Win32)
+	~/config/settings/vim/vimrc (Haiku)
+
 Note that creating a vimrc file will cause the 'compatible' option to be off
 by default.  See |compatible-default|.