Sync grammar with the upstream
Sync grammar with the upstream

Fixes #44

Vbif/VisualRust,vadimcn/VisualRust,cmr/VisualRust,Muraad/VisualRust,dlsteuer/VisualRust,xilec/VisualRust,PistonDevelopers/VisualRust,yacoder/VisualRust,dlsteuer/VisualRust,tempbottle/VisualRust,Stitchous/VisualRust,Boddlnagg/VisualRust,xilec/VisualRust,tempbottle/VisualRust,cmr/VisualRust,Connorcpu/VisualRust,PistonDevelopers/VisualRust,Muraad/VisualRust,drewet/VisualRust,drewet/VisualRust,Stitchous/VisualRust,vosen/VisualRust,yacoder/VisualRust,Vbif/VisualRust,Boddlnagg/VisualRust,vadimcn/VisualRust,Connorcpu/VisualRust,vosen/VisualRust