Improve wording in background tasks documentation

Refine wording for clarity and readability.

docs/en/docs/tutorial/background-tasks.md

@@ -1,8 +1,8 @@
 # Background Tasks { #background-tasks }
 
-You can define background tasks to be run *after* returning a response.
+You can define background tasks to be run after a response has been returned.
 
-This is useful for operations that need to happen after a request, but that the client doesn't really have to be waiting for the operation to complete before receiving the response.
+This is useful for operations that need to happen after a request, when the client does not need to wait for the operation to complete before receiving the response.
 
 This includes, for example: