rephrase messaging.mdx

Author: cratiu222

pages/builders/app-developers/bridging/messaging.mdx

@@ -220,7 +220,7 @@ We call this period of time the "challenge period" because it is the time during
 Optimistic Rollups are "optimistic" because they're based around the idea of publishing the *result* of a transaction to Ethereum without actually executing the transaction on Ethereum.
 In the "optimistic" case, this transaction result is correct and one can completely avoid the need to perform complicated (and expensive) logic on Ethereum.
 
-However, one still needs some way to prevent incorrect transaction results from being published in place of correct ones.
+However, one still needs to find a way to prevent incorrect transaction results from being published in place of correct ones.
 Here's where the "fault proof" comes into play.
 Whenever a transaction result is published, it's considered "pending" for a period of time known as the challenge period.
 During this period of time, anyone may re-execute the transaction *on Ethereum* in an attempt to demonstrate that the published result was incorrect.