Clarify that complex types and arrays can only be passed to functions through parameter aliases

complex types and arrays can be passed by value to functions as JSON, however the structure of the JSON may contain characters (urls, types prefixed with "#", etc.) which are not valid in the path of the URL. Thus, complex types/arrays may only be passed by value as parameters using a parameter alias (whose value is passed as a query option).

This is supported from the ABNF, but it takes some digging to figure out. It would be good to call this out in the prose.