Update fetch.bs

Co-authored-by: Barry Pollard <[email protected]>

Author: noamr

fetch.bs

@@ -6883,7 +6883,7 @@ pool of 640 kibibytes.
 
 <p>Out of the allocated quota for a {{Document}}, only 64 kibibytes can be used concurrently for the
 same reporting origin (the <a for=/>request</a>'s <a for=request>URL</a>'s <a for=url>origin</a>).
-This prevents a situation where particular 3rd party libraries would reserve quota
+This prevents a situation where particular 3rd-party libraries would reserve quota
 opportunistically, before they have data to send.
 
 <div class=example id=deferred-fetch-quota-examples>