remove deprecated general/sendMessage notification

Author: NiklasRentzCAU

plugins/de.cau.cs.kieler.klighd.lsp/src/de/cau/cs/kieler/klighd/lsp/KGraphLanguageClient.xtend

@@ -27,14 +27,6 @@ import org.eclipse.lsp4j.services.LanguageClient
  */
 interface KGraphLanguageClient extends LanguageClient {
 
-    /**
-     * Send to client if some message should be displayed. {@code type} is one of "info", "warn", and "error".
-     * 
-     * @deprecated Use the default LSP "window/showMessage" notification instead.
-     */
-    @JsonNotification("general/sendMessage")
-    def void sendMessage(String message, String type)
-    
     /**
      * Send to the client to replace the given range of the file given by the URI by the code string.
      */