Use recommended extensions as default formatters

.vscode/settings.json

@@ -2,6 +2,12 @@
     "files.associations": {
         "*.ts": "xml"
     },
+    "[xml]": {
+        "editor.defaultFormatter": "redhat.vscode-xml"
+    },
+    "[markdown]": {
+        "editor.defaultFormatter": "DavidAnson.vscode-markdownlint"
+    },
     "xml.format.maxLineWidth": 0,
     "editor.formatOnSave": true
 }