Update vscode-languageserver to version 9

Author: remcohaszing

package.json

@@ -39,7 +39,7 @@
     "unist-util-lsp": "^2.0.0",
     "vfile": "^6.0.0",
     "vfile-message": "^4.0.0",
-    "vscode-languageserver": "^8.0.0",
+    "vscode-languageserver": "^9.0.0",
     "vscode-languageserver-textdocument": "^1.0.0"
   },
   "devDependencies": {