Fix typo in gettingstarted.mdx (#583)

Author: adeleke5140

redis/sdks/ratelimit-ts/gettingstarted.mdx

@@ -115,7 +115,7 @@ When we use ratelimit in a serverless environment like CloudFlare Workers or Ver
 we need to be careful about making sure that the rate limiting operations complete correctly
 before the runtime ends after returning the response.
 
-This is important in two cases where we do some operations in the backgroung asynchronously after `limit` is called:
+This is important in two cases where we do some operations in the background asynchronously after `limit` is called:
 
 1. Using MultiRegion: synchronize Redis instances in different regions
 2. Enabling analytics: send analytics to Redis