Update user-privacy.md to use "project" not app

content/collections/api/en/user-privacy.md

@@ -44,7 +44,7 @@ Using this API doesn't prevent future user tracking for the deleted users. To le
 
 ## Limits
 
-The endpoint `/api/2/deletions/users` has a rate limit of 1 HTTP request per second. Each HTTP request can contain up to 100 `amplitude_ids` or `user_ids`. Additionally, there is a limit of 8 requests running in parallel for a given app. 
+The endpoint `/api/2/deletions/users` has a rate limit of 1 HTTP request per second. Each HTTP request can contain up to 100 `amplitude_ids` or `user_ids`. Additionally, there is a limit of 8 requests running in parallel for a given project. 
 
 Make up to 100 deletion requests per second if you batch 100 users in each request.