Docs: enhance FirebaseDynamicLinks comments (#13786)

Author: MojtabaHs

FirebaseDynamicLinks/Sources/Public/FirebaseDynamicLinks/FIRDynamicLinks.h

@@ -130,7 +130,7 @@ NS_SWIFT_NAME(DynamicLinks)
 /**
  * @method performDiagnosticsWithCompletion:
  * @abstract Performs basic FDL self diagnostic. Method effect on startup latency is quite small
- *    and no user-visble UI is presented. This method should be used for debugging purposes.
+ *    and no user-visible UI is presented. This method should be used for debugging purposes.
  *    App developers are encouraged to include output, generated by this method, to the support
  *    requests sent to Firebase support.
  * @param completionHandler Handler that will be called when diagnostic completes.