tree-sitter-fsh tree-sitter grammar and highlighting for FHIR Shorthand (FSH) References: https://github.com/FHIR/sushi/blob/master/antlr/src/main/antlr/FSH.g4 https://github.com/FHIR/sushi/blob/master/antlr/src/main/antlr/FSHLexer.g4