Docs experimental feature gate warning

[anvithagowda098]

Description

Adds warnings to the TCPRoute and TLSRoute setup guides to clarify that experimental Gateway API features require the KGW_ENABLE_EXPERIMENTAL_GATEWAY_API_FEATURES=true environment variable in kgateway 2.2 and later.

This helps prevent configuration issues when following the setup documentation for experimental Gateway API features.

Change Type

/kind documentation

Additional Notes

Updated:

• content/docs/envoy/main/setup/listeners/tcp.md
• content/docs/envoy/main/setup/listeners/tls-termination-tcproute.md

[kristin-kronstain-brown]

In kgateway 2.2 and later, the KGW_ENABLE_EXPERIMENTAL_GATEWAY_API_FEATURES variable defaults to true, so experimental features like TCPRoute and TLSRoute are enabled by default and don't require any extra configuration (see the 2.2 release notes). The variable only comes into play when you want to disable them by setting it to false. So the current wording reads a little backwards for the 2.2+ versions it targets. A quick flip to something like "In kgateway 2.2 and later, these experimental features are enabled by default; set KGW_ENABLE_EXPERIMENTAL_GATEWAY_API_FEATURES=false to disable them" would line it up with the actual behavior, though I'm not sure it's necessary.

[kristin-kronstain-brown]

Was there a scenario that came up that prompted this change? Maybe a little more context would help us understand how to fix this.