mention client_max_body_size in the web:locations area

[gilzow]

Where on docs.platform.sh should be changed?

https://docs.platform.sh/create-apps/app-reference/single-runtime-image.html#request-buffering

What exactly should be updated?

we do not expose the nginx configuration client_max_body_size directly to the customer, but there are parameters the user can adjust that change this value. We should add a keyword and/or a note regarding how they can adjust this value based on the max_request_size property of request_buffering

Additional context

H