patch 9.1.0559: translation of vim scripts can be improved

Problem:  translation of vim scripts can be improved
          (after v9.1.0509)
Solution: improve documentation, add tests, include missing
          libraries for the Windows CI
          (RestorerZ)

closes: #15100

Signed-off-by: RestorerZ <restorer@mail2k.ru>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index e28f185..2dc08e2 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 Jul 09
+*options.txt*	For Vim version 9.1.  Last change: 2024 Jul 11
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -6753,7 +6753,7 @@
 	  import/	files that are found by `:import`
 	  indent/	indent scripts |indent-expression|
 	  keymap/	key mapping files |mbyte-keymap|
-	  lang/		menu translations |:menutrans|
+	  lang/		message translations |:menutrans| and |multi-lang|
 	  menu.vim	GUI menus |menu.vim|
 	  pack/		packages |:packadd|
 	  plugin/	plugin scripts |write-plugin|