patch 8.2.1984: cannot use :vimgrep in omni completion

Problem:    Cannot use :vimgrep in omni completion, causing C completion to
            fail.
Solution:   Add the EX_LOCK_OK flag to :vimgrep. (closes #7292)
diff --git a/src/ex_cmds.h b/src/ex_cmds.h
index 4fe62ca..8873484 100644
--- a/src/ex_cmds.h
+++ b/src/ex_cmds.h
@@ -929,10 +929,10 @@
 	EX_RANGE|EX_FILE1|EX_NEEDARG|EX_CMDWIN|EX_LOCK_OK|EX_RESTRICT,
 	ADDR_LINES),
 EXCMD(CMD_lvimgrep,	"lvimgrep",	ex_vimgrep,
-	EX_RANGE|EX_BANG|EX_NEEDARG|EX_EXTRA|EX_NOTRLCOM|EX_TRLBAR|EX_XFILE,
+	EX_RANGE|EX_BANG|EX_NEEDARG|EX_EXTRA|EX_NOTRLCOM|EX_TRLBAR|EX_XFILE|EX_LOCK_OK,
 	ADDR_OTHER),
 EXCMD(CMD_lvimgrepadd,	"lvimgrepadd",	ex_vimgrep,
-	EX_RANGE|EX_BANG|EX_NEEDARG|EX_EXTRA|EX_NOTRLCOM|EX_TRLBAR|EX_XFILE,
+	EX_RANGE|EX_BANG|EX_NEEDARG|EX_EXTRA|EX_NOTRLCOM|EX_TRLBAR|EX_XFILE|EX_LOCK_OK,
 	ADDR_OTHER),
 EXCMD(CMD_lwindow,	"lwindow",	ex_cwindow,
 	EX_RANGE|EX_COUNT|EX_TRLBAR,
@@ -1673,10 +1673,10 @@
 	EX_BANG|EX_FILE1|EX_CMDARG|EX_ARGOPT|EX_TRLBAR,
 	ADDR_NONE),
 EXCMD(CMD_vimgrep,	"vimgrep",	ex_vimgrep,
-	EX_RANGE|EX_BANG|EX_NEEDARG|EX_EXTRA|EX_NOTRLCOM|EX_TRLBAR|EX_XFILE,
+	EX_RANGE|EX_BANG|EX_NEEDARG|EX_EXTRA|EX_NOTRLCOM|EX_TRLBAR|EX_XFILE|EX_LOCK_OK,
 	ADDR_OTHER),
 EXCMD(CMD_vimgrepadd,	"vimgrepadd",	ex_vimgrep,
-	EX_RANGE|EX_BANG|EX_NEEDARG|EX_EXTRA|EX_NOTRLCOM|EX_TRLBAR|EX_XFILE,
+	EX_RANGE|EX_BANG|EX_NEEDARG|EX_EXTRA|EX_NOTRLCOM|EX_TRLBAR|EX_XFILE|EX_LOCK_OK,
 	ADDR_OTHER),
 EXCMD(CMD_vim9script,	"vim9script",	ex_vim9script,
 	EX_CMDWIN|EX_LOCK_OK,