Update docs/node/nodes/gateway.md

Co-authored-by: Steffen Vogel <steffen.vogel@opal-rt.com>
Signed-off-by: al3xa23 <140614263+al3xa23@users.noreply.github.com>

Author: al3xa23

docs/node/nodes/gateway.md

@@ -56,7 +56,7 @@ nodes = {
 
 The usage of this node is similar to [`api`](api.md) node-type.
 The following [`curl`](https://curl.se/) commands are examples for calling gRPC methods via the HTTP API.
-The input for a gRPC call can be either the body of http request or input data from another node (via a [path](../config/paths.md)).
+The input for a gRPC call can be either the body of HTTP request or input data from another node (via a [path](../config/paths.md)).
 If the http request body is empty, the input from other node will be used.
 
 Since this node-type does not implement the gRPC server, it needs to be added manually. A description is available [here](https://www.acs.eonerc.rwth-aachen.de/global/show_document.asp?id=aaaaaaaadidaesd).