Update devcontainer.json

Author: Chuxel

containers/docker-existing-docker-compose/.devcontainer/devcontainer.json

@@ -8,6 +8,9 @@
         "../docker-compose.yml",
         "docker-compose.yml"
     ],
+    
+    // "The extensions property works as-is"
+    "extensions": []
 
     // "The 'service' property is the name of the service for the container that VS Code should"
     // "use. Update this value and .devcontainer/docker-compose.yml to the real service name."
@@ -16,4 +19,9 @@
     // "The optional 'workspaceFolder' property is the path VS Code should open by default when"
     // "connected. This is typically a file mount in .devcontainer/docker-compose.yml"
     "workspaceFolder": "/workspace"
+
+    // "Other notes:"
+    // "- The appPorts property is not supported in the Docker Compose case. Add the ports into"
+    // "  the docker-compose.yml in the .devcontainer folder instead." 
+    // "- The runArgs property is also not supported."
 }