Align network connection doc with libp2p and java-tron source code

[abn2357]

Summary

Reviewed docs/using_javatron/connecting_to_tron.md against the libp2p source and java-tron config.conf, and corrected several inaccuracies.

• Expanded the Number of Node Connections section to cover minConnections, minActiveConnections, and maxConnectionsWithSameIp (previously only maxConnections was documented). The new wording reflects how the parameters actually interact in libp2p's ConnPoolService and ChannelManager: trust-peer handling, that outbound bypasses maxConnections, and the startup clamping done in TronNetService.
• Corrected the HTTP port in API examples from 16887 to 8090, the actual default node.http.fullNodePort in config.conf. Applied in both connecting_to_tron.md and private_network.md.
• Genesis block timestamp comment now matches the wording in java-tron's config.conf (# Genesis block timestamp, milli seconds), removing the misleading #2017-8-26 12:00:00 annotation next to a literal "0".
• Fixed typo enironments → environments.

Test plan

• Render the doc locally and confirm the new bullet list and code block under "Number of Node Connections" display correctly.
• Verify the two curl examples (getnodeinfo, getnowblock) work against a local java-tron fullnode using port 8090.