Update Running and Writing Tests for Sia.md
Update Running and Writing Tests for Sia.md

fix anchor tags on headers
mtlynch/Sia,MrStrong/Sia,ericflo/Sia,NebulousLabs/Sia,ChrisSchinnerl/Sia,mharkus/Sia,MrStrong/Sia,mtlynch/Sia,ChrisSchinnerl/Sia,ericflo/Sia,NebulousLabs/Sia,mharkus/Sia