specify clang for c++ formatting conventions

.vscode/extensions.json

@@ -2,6 +2,7 @@
     // See http://go.microsoft.com/fwlink/?LinkId=827846
     // for the documentation about the extensions.json format
     "recommendations": [
-        "platformio.platformio-ide"
+        "platformio.platformio-ide",
+        "xaver.clang-format"
     ]
 }

.vscode/settings.json

@@ -77,5 +77,6 @@
             "--java_out=/tmp",
             "-I=/home/kevinh/development/meshtastic/meshtastic-esp32/proto"
         ]
-    }    
+    },
+    "editor.formatOnSave": true
 }