Update fallback.adoc

Fix a typo.

Closes gh-33721

Author: boulce

framework-docs/modules/ROOT/pages/web/websocket/fallback.adoc

@@ -238,7 +238,7 @@ heartbeats to be exchanged, the SockJS heartbeats are disabled.
 
 The Spring SockJS support also lets you configure the `TaskScheduler` to
 schedule heartbeats tasks. The task scheduler is backed by a thread pool,
-with default settings based on the number of available processors. Your
+with default settings based on the number of available processors. You
 should consider customizing the settings according to your specific needs.