init, doc: improve -onlynet help and tor/i2p documentation

and harmonize them as follows

- s/outgoing/automatic outbound/
- s/Incoming/Inbound and manual/ (are not affected by this option.)
- s/only through network/only to network/
- s/this option. This option/this option. It/
- s/network types/networks/

and also pick up a few nits in doc/p2p-bad-ports.md

doc/tor.md

@@ -55,10 +55,10 @@ outgoing connections, but more is possible.
     -seednode=X     SOCKS5. In Tor mode, such addresses can also be exchanged with
                     other P2P nodes.
 
-    -onlynet=onion  Make outgoing connections only to .onion addresses. Incoming
-                    connections are not affected by this option. This option can be
-                    specified multiple times to allow multiple network types, e.g.
-                    onlynet=onion, onlynet=i2p.
+    -onlynet=onion  Make automatic outbound connections only to .onion addresses.
+                    Inbound and manual connections are not affected by this option.
+                    It can be specified multiple times to allow multiple networks,
+                    e.g. onlynet=onion, onlynet=i2p.
 
 In a typical situation, this suffices to run behind a Tor proxy: