Add support for Fn+PrtSc on Thinkpads

Add support for Fn+PrtSc on Thinkpads

This adds support for Fn+PrtSc on my Lenovo Thinkpad Extreme gen 2. Judging by the picture on the key, it should probably instead of prog2 be "selective_screenshot" (that is a possible value from judging this list https://gist.githubusercontent.com/samvel1024/02e5675e04f9d84f098e98bcd0e1ea12/raw/e18d950ce571b4ff5c832cc06406e9a6afece132/keynames.txt ) but that does not register with evtest at all. With this change, evtest reports:

```
Event: time 1661081631.027773, type 1 (EV_KEY), code 149 (KEY_PROG2), value 1
Event: time 1661081631.027773, -------------- SYN_REPORT ------------
Event: time 1661081631.027886, type 1 (EV_KEY), code 149 (KEY_PROG2), value 0
Event: time 1661081631.027886, -------------- SYN_REPORT ------------
```

I am not sure if systemd is the right place to add this, if not, please refer me somewhere else.