Add comment about overriding container_push destination (#2221)

* Add comment about overriding container_push destination.

* Makes more sense

* Add note about needing "--" in blaze run

* Blaze->bazel

Author: coryrc

container/push.bzl

@@ -219,6 +219,10 @@ container_push_ = rule(
 )
 
 # Pushes a container image to a registry.
+# You can override some arguments by including adding arguments when running blaze run.
+# Additional arguments will be sent to the command listed in the _pusher rule above.
+# Most common use is adding --dst=myregistry/mypath:debugtag.
+# Use `bazel run //target:push -- -help` to get a printing of possible options.
 def container_push(name, format, image, registry, repository, **kwargs):
     container_push_(
         name = name,