Remove deprecated convenience constructors in xtend protocol files

There are numerous constructors in protocol files that are deprecated, such as one of the constructors of [WorkspaceEditCapabilities](https://github.com/eclipse-lsp4j/lsp4j/blob/193c3bca435550b1f89d333d81002275988eeefb/org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/Protocol.xtend#L107-L113)