patch 9.1.1374: completion: 'smartcase' not respected when filtering matches

Problem:  Currently, 'smartcase' is respected when completing keywords
          using <C-N>, <C-P>, <C-X><C-N>, and <C-X><C-P>. However, when
          a user continues typing and the completion menu is filtered
          using cached matches, 'smartcase' is not applied. This leads
          to poor-quality or irrelevant completion suggestions, as shown
          in the example below.
Solution: When filtering cached completion items after typing additional
          characters, apply case-sensitive comparison if 'smartcase' is
          enabled and the typed pattern includes uppercase characters.
          This ensures consistent and expected completion behavior.
          (Girish Palya)

closes: #17271

Signed-off-by: Girish Palya <girishji@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index bed14ab..f3824cd 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -1,4 +1,4 @@
-*options.txt*	For Vim version 9.1.  Last change: 2025 May 07
+*options.txt*	For Vim version 9.1.  Last change: 2025 May 08
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -7742,9 +7742,11 @@
 	Override the 'ignorecase' option if the search pattern contains upper
 	case characters.  Only used when the search pattern is typed and
 	'ignorecase' option is on.  Used for the commands "/", "?", "n", "N",
-	":g" and ":s".  Not used for "*", "#", "gd", tag search, etc.  After
-	"*" and "#" you can make 'smartcase' used by doing a "/" command,
-	recalling the search pattern from history and hitting <Enter>.
+	":g" and ":s" and when filtering matches for the completion menu
+	|compl-states|.
+	Not used for "*", "#", "gd", tag search, etc.  After "*" and "#" you
+	can make 'smartcase' used by doing a "/" command, recalling the search
+	pattern from history and hitting <Enter>.
 	NOTE: This option is reset when 'compatible' is set.
 
 			     *'smartindent'* *'si'* *'nosmartindent'* *'nosi'*