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/src/ex_cmds.h b/src/ex_cmds.h
index 2bbf5ef..3cb8a18 100644
--- a/src/ex_cmds.h
+++ b/src/ex_cmds.h
@@ -1700,6 +1700,9 @@
 EXCMD(CMD_unhide,	"unhide",	ex_buffer_all,
 	EX_RANGE|EX_COUNT|EX_TRLBAR,
 	ADDR_OTHER),
+EXCMD(CMD_uniq,		"uniq",		ex_uniq,
+	EX_RANGE|EX_DFLALL|EX_WHOLEFOLD|EX_BANG|EX_EXTRA|EX_NOTRLCOM|EX_MODIFY,
+	ADDR_LINES),
 EXCMD(CMD_unlet,	"unlet",	ex_unlet,
 	EX_BANG|EX_EXTRA|EX_NEEDARG|EX_SBOXOK|EX_CMDWIN|EX_LOCK_OK,
 	ADDR_NONE),