sequencer: always allow tab after command name

The code that parses the todo list allows an unabbreviated command name
to be followed by a space or a tab, but if the command name is
abbreviated it only allows a space after it. Fix this inconsistency.

Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sequencer.c

@@ -2100,7 +2100,7 @@ static int parse_insn_line(struct repository *r, struct todo_item *item,
 		if (skip_prefix(bol, todo_command_info[i].str, &bol)) {
 			item->command = i;
 			break;
-		} else if ((bol + 1 == eol || bol[1] == ' ') &&
+		} else if ((bol + 1 == eol || bol[1] == ' ' || bol[1] == '\t') &&
 			   *bol == todo_command_info[i].c) {
 			bol++;
 			item->command = i;