Rename 'name' member of ActionDescription to 'customName'

* This is a deliberate break of compatibility since the field is now often
  empty, for non-markers. This means code will get a more explicit error when
  the name is being referenced, so it can be updated to fetch the name it needs
  as needed.

docs/python_api/examples/renderdoc/fetch_counters.py

@@ -62,7 +62,7 @@ def sampleCode(controller):
 			val = r.value.u64
 
 		if val == 0:
-			print("EID %d '%s' had no samples pass depth/stencil test!" % (r.eventId, draw.name))
+			print("EID %d '%s' had no samples pass depth/stencil test!" % (r.eventId, draw.GetName(controller.GetStructuredFile())))
 
 def loadCapture(filename):
 	# Open a capture file handle