doc: fix typo in http2 endAfterHeaders description

PR-URL: #42060
Reviewed-By: Robert Nagy <ronagy@icloud.com>
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Rich Trott <rtrott@gmail.com>

doc/api/http2.md

@@ -1205,7 +1205,7 @@ added: v10.11.0
 
 * {boolean}
 
-Set the `true` if the `END_STREAM` flag was set in the request or response
+Set to `true` if the `END_STREAM` flag was set in the request or response
 HEADERS frame received, indicating that no additional data should be received
 and the readable side of the `Http2Stream` will be closed.