[hasannadeem]

Fixes #1671.

TCPServer.new([hostname,] port) passes both arguments to getaddrinfo, so the host can be nil and the port can be a String, either a number or a service name:

TCPServer.new(0)                    # OK with the current signature
TCPServer.new("0")                  # rejected: String port
TCPServer.new("127.0.0.1", "8080")  # rejected: String port
TCPServer.new(nil, 0)               # rejected: nil host

All four work in Ruby, but the signature was (?String host, Integer port) -> untyped. This changes it to (?String? host, Integer | String port) -> void, and adds TCPServerSingletonTest#test_new for each of these calls. With the old signature the test fails at the first String port ("Call trace does not match one of method definitions"). With the new one it passes, and so do the other socket tests and Net_HTTP_test.rb. rbs validate and rubocop pass too (Ruby 3.4.4).

I kept to the common types and left out some rarer ones Ruby also accepts: an Integer IPv4 address as the host, to_str objects, and a nil port. A to_int port is rejected by Ruby (no implicit conversion of Object into String), so ::int would be wrong for the port.

The rest of the socket signatures, such as TCPSocket#initialize and Socket.tcp_server_loop, also type ports as Integer only. I haven't changed those here, to keep this to the method in the issue.