Add more detail to the remote build doc

Author: shs96c

CONTRIBUTING.md

@@ -326,3 +326,7 @@ To access the EngFlow RBE, a developer needs to be granted access to our project
 container repository. Once that has been done, then any bazel command can be run
 remotely by using `--config=remote`. For example: `bazel build --config=remote
 grid` or `bazel test --config=remote java/test/...`
+
+When you run a remote build, one of the first lines of output from Bazel will 
+include a link to the EngFlow UI so you can track the progress of the build and
+gather information about the efficiency of the build.