patch 8.2.3462: ModeChanged only uses one character for new_mode and old_mode

Problem:    The ModeChanged event only uses one character for the new_mode and
            old_mode values.
Solution:   Pass one as first argument to mode(). (issue #8856)
diff --git a/src/misc1.c b/src/misc1.c
index b4a4a8c..8e21f1e 100644
--- a/src/misc1.c
+++ b/src/misc1.c
@@ -2657,7 +2657,7 @@
 #if defined(FEAT_EVAL) || defined(PROTO)
     dict_T	    *v_event;
     typval_T	    rettv;
-    typval_T	    tv;
+    typval_T	    tv[2];
     char_u	    *pat_pre;
     char_u	    *pat;
 
@@ -2666,8 +2666,10 @@
 
     v_event = get_vim_var_dict(VV_EVENT);
 
-    tv.v_type = VAR_UNKNOWN;
-    f_mode(&tv, &rettv);
+    tv[0].v_type = VAR_NUMBER;
+    tv[0].vval.v_number = 1;	    // get full mode
+    tv[1].v_type = VAR_UNKNOWN;
+    f_mode(tv, &rettv);
     (void)dict_add_string(v_event, "new_mode", rettv.vval.v_string);
     (void)dict_add_string(v_event, "old_mode", last_mode);
     dict_set_items_ro(v_event);