Update images in `citationkeypatterns.md`

[subhramit]

The following option does't exist in the library menu:

Rather, it exists inside library properties (at least in Windows).
Since the rest of the pictures are taken from a jabref running on mac, ideally a picture running on mac should be used for the fix as well for uniformity.
Have to check the other pictures as well.

[Siedlerchr]