Update README.md

Author: dklilley

README.md

@@ -17,6 +17,7 @@ MATLAB language server implements several Language Server Protocol features and
 * Go to definition — [definitionProvider](https://microsoft.github.io/language-server-protocol/specifications/specification-current/#textDocument_definition)
 * Go to references — [referencesProvider](https://microsoft.github.io/language-server-protocol/specifications/specification-current/#textDocument_references)
 * Document symbols — [documentSymbol](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_documentSymbol)
+* Code folding - [foldingRangeProvider](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_foldingRange)
 * Symbol rename - [renameProvider](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_rename)
 
 ## Clients