changed block from code to paragraph (#3330)

README.md

@@ -301,13 +301,14 @@ Alternatively, see the section on remotely managed plugin versions below.
    ```
 
    #### 3. External configuration
-      If you do not want to (or cannot) modify the proto file for use with gRPC-Gateway you can
-      alternatively use an external
-      [gRPC Service Configuration](https://cloud.google.com/endpoints/docs/grpc/grpc-service-config) file.
-      [Check our documentation](https://grpc-ecosystem.github.io/grpc-gateway/docs/mapping/grpc_api_configuration/)
-      for more information. This is best combined with the `standalone=true` option
-      to generate a file that can live in its own package, separate from the files
-      generated by the source protobuf file.
+
+   If you do not want to (or cannot) modify the proto file for use with gRPC-Gateway you can
+   alternatively use an external
+   [gRPC Service Configuration](https://cloud.google.com/endpoints/docs/grpc/grpc-service-config) file.
+   [Check our documentation](https://grpc-ecosystem.github.io/grpc-gateway/docs/mapping/grpc_api_configuration/)
+   for more information. This is best combined with the `standalone=true` option
+   to generate a file that can live in its own package, separate from the files
+   generated by the source protobuf file.
 
    Here's what a `buf.gen.yaml` file might look like with this option enabled: