message: docs: Update proto format tool path
  Small update on proto_format path.
diff: @@ -126,7 +126,7 @@ To add an extension config to the API, the steps below should be followed:
  [Buffer filter config](envoy/config/filter/http/buffer/v2/buffer.proto) as an example of `v2`.
  1. Place the v2 extension configuration `.proto` in `api/envoy/config`, e.g.
  `api/envoy/config/filter/http/foobar/v2/foobar.proto` together with an initial BUILD file:
  - ```
  + ```bazel
  load("@envoy_api//bazel:api_build_system.bzl", "api_proto_package")
  licenses(["notice"]) # Apache 2
  @@ -141,7 +141,7 @@ To add an extension config to the API, the steps below should be followed:
  1. If this is still WiP and subject to breaking changes, import
  `udpa/annotations/status.proto` and set `option (udpa.annotations.file_status).work_in_progress = true;`.
  1. Add a reference to the v2 extension config in (1) in [api/docs/BUILD](docs/BUILD).
  -1. Run `./tools/proto_format fix`. This should regenerate the `BUILD` file,
  +1. Run `./tools/proto_format/proto_format.sh fix`. This should regenerate the `BUILD` file,
  reformat `foobar.proto` as needed and also generate the v3 extension config,
  together with shadow API protos.
  1. `git add api/ generated_api_shadow/` to add any new files to your Git index.
  