SIG groupings

The list of SIGs is pretty long and because the abbreviations are somewhat cryptic it can be hard to comprehend at a glance. It occurred to me that the SIGs can be grouped as follows:

- **Core Methods:** ANN DAT FSM GEN LEX MEDIA MOL MORPHON NLL PARSE REP SEM TYP
- **Applications:** DIAL MT SEC SLPAT SLT SUMM
- **Domains:** BIOMED EDU FinTech HUM Writ WAC
- **Languages:** ARAB EL HAN SEA SEMITIC SLAV Turk UL UR

Not perfect (there are some borderline ones, like TYP, HUM, Writ) but is it useful? If so it might go on the homepage.