Merge #20965: net, rpc: return NET_UNROUTABLE as not_publicly_routable, automate helps

96635e6177 init: use GetNetworkNames() in -onlynet help (Jon Atack)
0dbde700a6 rpc: use GetNetworkNames() in getnetworkinfo and getpeerinfo helps (Jon Atack)
1c3af37881 net: create GetNetworkNames() (Jon Atack)
b45eae4d53 net: update NET_UNROUTABLE to not_publicly_routable in GetNetworkName() (Jon Atack)

Pull request description:

  per the IRC discussion today at http://www.erisian.com.au/bitcoin-core-dev/log-2021-01-19.html#l-87

  - return a more helpful string name for `Network::NET_UNROUTABLE`: "not_publicly_routable" instead of "unroutable"
  - update the RPC getpeerinfo "network" help, and automate it and the getnetworkinfo "network#name" and the -onlynet help doc generation

ACKs for top commit:
  theStack:
    re-ACK 96635e6177 🌳
  MarcoFalke:
    review ACK 96635e6177 🐗

Tree-SHA512: 511a7d987126b48a7a090739aa7c4964b6186a3ff8f5f7eec9233dd816c6b7a6dc91b3ea6b824aa68f218a8a3ebdc6ffd214e9a88af38f2bf23f3257c4284c3a

test/functional/rpc_net.py

@@ -104,6 +104,9 @@ class NetTest(BitcoinTestFramework):
         assert_equal(peer_info[1][0]['connection_type'], 'manual')
         assert_equal(peer_info[1][1]['connection_type'], 'inbound')
 
+        # Check dynamically generated networks list in getpeerinfo help output.
+        assert "(ipv4, ipv6, onion, not_publicly_routable)" in self.nodes[0].help("getpeerinfo")
+
     def test_getnettotals(self):
         self.log.info("Test getnettotals")
         # Test getnettotals and getpeerinfo by doing a ping. The bytes
@@ -152,6 +155,9 @@ class NetTest(BitcoinTestFramework):
         for info in network_info:
             assert_net_servicesnames(int(info["localservices"], 0x10), info["localservicesnames"])
 
+        # Check dynamically generated networks list in getnetworkinfo help output.
+        assert "(ipv4, ipv6, onion)" in self.nodes[0].help("getnetworkinfo")
+
     def test_getaddednodeinfo(self):
         self.log.info("Test getaddednodeinfo")
         assert_equal(self.nodes[0].getaddednodeinfo(), [])