Fix inaccurate comment describing socket configuration in kamailio.cfg

[Copilot]

Addresses review feedback on PR #113 regarding a misleading comment in the SET_SOCKET route documentation.

Changes

• LOCALNETWORKS comment: Changed from "uses PRIVATE_IP for advertised address" to "sets the socket to PRIVATE_IP:6060 (specific IP:port)" to accurately reflect $fs = PRIVATE_IP + ":6060";
• INTERNAL_NETWORK comment: Updated to include port number ("SERVICE_IP:5060") for consistency with the actual implementation $fs = SERVICE_IP + ":5060";

Both comments now accurately describe the socket assignment behavior rather than suggesting advertised address usage.

# Before
# - LOCALNETWORKS: uses PRIVATE_IP for advertised address
# - INTERNAL_NETWORK: forces socket to SERVICE_IP for traffic to Asterisk

# After  
# - LOCALNETWORKS: sets the socket to PRIVATE_IP:6060 (specific IP:port)
# - INTERNAL_NETWORK: forces socket to SERVICE_IP:5060 (specific IP:port) for traffic to Asterisk

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