docs: clarify wording in subscriptions regarding starting positions

Author: w1am

docs/api/subscriptions.md

@@ -46,7 +46,7 @@ When you subscribe to a stream with link events (e.g., `$ce` category stream), s
 
 ## Subscribing from a Position
 
-Both stream and `$all` subscriptions accept a starting position if you want to read from a specific point onward. If events already exist at the position you subscribe to, they will be read on the server side and sent to the subscription.
+Both stream and `$all` subscriptions accept a starting position if you want to read from a specific point onward. If events already exist after the position you subscribe to, they will be read on the server side and sent to the subscription.
 
 Once caught up, the server will push any new events received on the streams to the client. There is no difference between catching up and live on the client side.
 
@@ -418,4 +418,4 @@ The client allows you to configure backpressure to control how many events are b
 
 By default, the client requests up to 512 events at a time. It will automatically
 request more events when the number of buffered (unprocessed) events falls below
-25% of the batch size.
+25% of the batch size.