Change instrument name FORS2_VLT to FORS2

Hi,

to be consistent with the instrument labels, change FORS2_VLT to FORS2. On Fritz, a FORS2 instrument is associated with HET. A quick search on the HET page doesn't show such an instrument. Their spectrographs are called LRS2 and HRS2. Could you check where HET/FORS2 comes from?

Cheers,

Steve