patch 9.1.1476: no easy way to deduplicate text

Problem:  no easy way to deduplicate text
Solution: add the :uniq ex command
          (Hirohito Higashi)

closes: #17538

Signed-off-by: Hirohito Higashi <h.east.727@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/index.txt b/runtime/doc/index.txt
index ff27994..11c0efd 100644
--- a/runtime/doc/index.txt
+++ b/runtime/doc/index.txt
@@ -1,4 +1,4 @@
-*index.txt*     For Vim version 9.1.  Last change: 2025 Jun 02
+*index.txt*     For Vim version 9.1.  Last change: 2025 Jun 23
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -1740,6 +1740,7 @@
 |:unabbreviate|	:una[bbreviate]	remove abbreviation
 |:unhide|	:unh[ide]	open a window for each loaded file in the
 				buffer list
+|:uniq|		:uni[q]		uniq lines
 |:unlet|	:unl[et]	delete variable
 |:unlockvar|	:unlo[ckvar]	unlock variables
 |:unmap|	:unm[ap]	remove mapping