guess: Move the cursor to the first peg position after a guess

It's annoying having to move it to the left each time.  I suppose I
could enter the second guess in reverse order, but then I'd need to move
the cursor all the way to the right to submit it, which is just as bad.

guess.c

@@ -507,7 +507,7 @@ static void game_changed_state(game_ui *ui, const game_state *oldstate,
     ui->markable = is_markable(&newstate->params, ui->curr_pegs);
     /* Clean up cursor position */
     if (!ui->markable && ui->peg_cur == newstate->solution->npegs)
-	ui->peg_cur--;
+	ui->peg_cur = 0;
 }
 
 #define PEGSZ   (ds->pegsz)