patch 8.2.4012: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move the last error messages to errors.h.
diff --git a/src/vim9compile.c b/src/vim9compile.c
index f1a6a03..da93c1b 100644
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -1109,7 +1109,7 @@
 	*dest = dest_option;
 	if (cmdidx == CMD_final || cmdidx == CMD_const)
 	{
-	    emsg(_(e_cannot_lock_an_option));
+	    emsg(_(e_cannot_lock_option));
 	    return FAIL;
 	}
 	p = name;