patch 9.1.1830: MS-Windows: Dark mode titlebar is not configurable

Problem:  MS-Windows: Dark mode titlebar is not configurable
          (after v9.1.1813)
Solution: Revert patch v9.1.1813

Revert "patch 9.1.1813: MS-Windows: title bar is always white"
This reverts commit dddde9ce12.

related: #18282

Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/doc/gui_w32.txt

@@ -1,4 +1,4 @@
-*gui_w32.txt*   For Vim version 9.1.  Last change: 2025 Sep 29
+*gui_w32.txt*   For Vim version 9.1.  Last change: 2025 Aug 06
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -488,12 +488,4 @@ VIM_KEYCODE_TRANS_STRATEGY can be set to the desired value ("experimental" or
         set VIM_KEYCODE_TRANS_STRATEGY=experimental
         gvim.exe
 <
-
-Title Bar's Behaviour			    *gui-w32-title-bar-behaviour*
-
-The color of the gVim title bar (sometimes also called the caption bar) is
-treated as part of the application's background.  Starting with Windows 11,
-it follows the background color defined by |hl-Normal|, so it matches the
-background of the current colorscheme.
-
  vim:tw=78:sw=4:ts=8:noet:ft=help:norl:

runtime/doc/tags

@@ -8223,7 +8223,6 @@ gui-w32-cmdargs	gui_w32.txt	/*gui-w32-cmdargs*
 gui-w32-dialogs	gui_w32.txt	/*gui-w32-dialogs*
 gui-w32-printing	gui_w32.txt	/*gui-w32-printing*
 gui-w32-start	gui_w32.txt	/*gui-w32-start*
-gui-w32-title-bar-behaviour	gui_w32.txt	/*gui-w32-title-bar-behaviour*
 gui-w32-various	gui_w32.txt	/*gui-w32-various*
 gui-w32-windowid	gui_w32.txt	/*gui-w32-windowid*
 gui-w32s	os_win32.txt	/*gui-w32s*

runtime/doc/version9.txt

@@ -41750,8 +41750,6 @@ Plugins~
 Platform specific ~
 - MS-Winodws: Paths like "\Windows" and "/Windows" are now considered to be
   absolute paths (to the current drive) and no longer relative.
-- MS-Windows: The title bar background follows the |hl-Normal| highlighting
-  group background color.
 - macOS: increase default scheduler priority to TASK_DEFAULT_APPLICATION.
 
 Others: ~