[Doc] Relevance between max-header-size and http2-max-header-list-size attributes should be clarified and documented

There is not very clear what should be intended behavior in case of using both
http2-max-header-list-size and max-header-size attributes in case of HTTP/2 requests.

Current behavior seems to be that if http2-max-header-list-size is defined, then it takes precedence ignoring the value of general header limitation attributes for the listener.

Not sure what is better behavior whether to take value which limits the values more (=> the lower number) or that the value with http2 prefix takes precedence (current behavior). Either way it should be at least documented.
sdouglas1@redhat.com WDYT?