Minor ColumnVCFInfo fixes (Export VCF info)

This should be upper case?
```
ID=gnomAD_HOM_ALT,number=.,type=I,descr: Count of homozygous individuals
```

Description is wrong:

```
##INFO=
```

These should probably have GNOMAD in front of them?
```
ID=SV_overlap_AF,number=1,type=S,descr: gnomAD SV (StructuralVariantOverlap): frequency of overlapping SV
ID=SV_overlap_coords,number=1,type=S,descr: gnomAD SV (StructuralVariantOverlap): coordinates
ID=SV_overlap_name,number=1,type=S,descr: gnomAD SV (StructuralVariantOverlap): name of overlapping SV
ID=SV_overlap_PC,number=1,type=S,descr: gnomAD SV (StructuralVariantOverlap): percent of input SV covered by reference SV
```