Clarify subject format

Co-authored-by: Dylan <[email protected]>

README.md

@@ -158,7 +158,7 @@ Dots are valid in scope names and should be used for logical serration as above.
 
 ### `query.{uuid}`
 
-All items, errors and status updates get sent over a subject named after the Query's UUID. See `QueryResponse`.
+All items, errors and status updates get sent over a subject named after the Query's UUID. This UUID should be in five groups separated by hyphens, in the form 8-4-4-4-12 for a total of 36 characters, with all letters being lower case e.g. `bcee962c-ca60-479b-8a96-ab970d878392` See `QueryResponse`.
 
 ### `cancel.all`