Teach 'network-lookup-address-info' to validate numeric addresses

Teach 'network-lookup-address-info' to validate numeric addresses

* src/process.c (Fnetwork_lookup_address_info): Add optional 'hints'
argument, pass AI_NUMERICHOST to 'getaddrinfo' if it's 'numeric'.
(syms_of_process): Add 'numeric' symbol.
* doc/lispref/processes.texi (Misc Network): Expunge passive voice.
Update 'network-lookup-address-info' description.
* test/src/process-tests.el (lookup-hints-specification):
(lookup-hints-values): Test new functionality.
* etc/NEWS: Announce change.