Mention that buildifier has bzl-visibility
It's not a guarantee that users don't load private APIs but it's the best we've got, and worth noting here.
Closes
@@ -187,6 +187,10 @@ for more details.
`load` statements are currently not subject to visibility. It is possible to
load a `bzl` file anywhere in the workspace.
+However, users may choose to run the Buildifier linter.
+The [bzl-visibility](https://github.com/bazelbuild/buildtools/blob/master/WARNINGS.md#bzl-visibility) check
+provides a warning if users `load` from beneath a subdirectory named `internal` or `private`.
+
## Visibility of implicit dependencies
Some rules have implicit dependencies. For example, a C++ rule might implicitly
