lux: download video from bilibili.com which url not end with av+id will not exit after downloading.

as the title says, tests below:

tony@tony-VirtualBox:~/下载$ 
   Site:   哔哩哔哩 bilibili.com
  Title:   【Perfume】 Music Station （2018.02.23） 无限未来
   Type:   video
Quality:   高清 720P
   Size:   52.13 MiB (54661154 Bytes)

 52.13 MiB / 52.13 MiB [============================] 100.00% 540.23 KiB/s 1m38s

[1]+  已完成               annie https://www.bilibili.com/video/av19976437?from=search

after downloading, the process will not exit, you should enter the “enter” key to exit.