修复输出\b后未修改背景的错误 (#27)

* 修复输出\b后未修改背景的错误

* Update textui.c

Co-authored-by: login <longjin@ringotek.cn>

kernel/lib/libUI/textui.c

@@ -236,6 +236,7 @@ int textui_putchar_window(struct textui_window_t *window, uint16_t character, ui
             if (tmp >= 0)
             {
                 window->vlines.chromatic[window->vline_operating].chars[tmp].c = ' ';
+                window->vlines.chromatic[window->vline_operating].chars[tmp].BKcolor = BKcolor & 0xffffff;
                 textui_refresh_characters(window, window->vline_operating, tmp, 1);
             }
         }
@@ -335,4 +336,4 @@ int textui_init()
 
     uart_send_str(COM1, "text ui initialized\n");
     return 0;
-}
+}