Rename 'draw' or 'drawcall' to action

* There's not a good accepted terminology for this kind of event, and for
  historical reasons 'drawcall' has been the accepted term, even though
  that can be quite confusing when a dispatch or a copy is a 'drawcall'.
* This is particularly highlighted by the event browser filters where
  $draw() includes draws and dispatches, but $dispatch() only includes
  dispatches, it's hard to intuitively understand why $draw() matches all
  of these calls.
* As a result we've defined the term 'action' to cover these types of
  events in the same way that we defined 'event' in the first place to
  mean a single atomic API call.

docs/python_api/examples/renderdoc/index.rst

@@ -26,7 +26,7 @@ In order to help with this, the examples are organised such that most code is wr
         cap.Shutdown()
 
 .. toctree::
-    iter_draws
+    iter_actions
     fetch_shader
     fetch_counters
     save_texture