DiagnosticSeverity according to implementation https://github.com/Microsoft/vscode-languageserver-node instead of documentation https://github.com/Microsoft/language-server-protocol/blob/master/protocol.md;
src/Pure
src/FOL
src/HOL
src/ZF
src/CCL
src/CTT
src/Cube
src/FOLP
src/LCF
src/Sequents
src/Doc
src/Tools