patch 8.2.0839: dropping modifier when putting a character back in typeahead

Problem:    Dropping modifier when putting a character back in typeahead.
Solution:   Add modifier to ins_char_typebuf(). (closes #6158)
diff --git a/src/message.c b/src/message.c
index 04dc401..45217e2 100644
--- a/src/message.c
+++ b/src/message.c
@@ -1258,7 +1258,7 @@
 	{
 	    // Put the character back in the typeahead buffer.  Don't use the
 	    // stuff buffer, because lmaps wouldn't work.
-	    ins_char_typebuf(c);
+	    ins_char_typebuf(vgetc_char, vgetc_mod_mask);
 	    do_redraw = TRUE;	    // need a redraw even though there is
 				    // typeahead
 	}
@@ -3712,7 +3712,7 @@
 		if (c == ':' && ex_cmd)
 		{
 		    retval = dfltbutton;
-		    ins_char_typebuf(':');
+		    ins_char_typebuf(':', 0);
 		    break;
 		}