docs(2.1.x): replace unsupported regex rewrite section

[anvithagowda098]

Description

The TrafficPolicy urlRewrite field does not exist in v2.1.x . The Regex rewrite section on the v2.1.x path rewrites page incorrectly documented this feature, causing API errors for users who followed it.

Replaced the entire Regex rewrite section with a callout noting the feature is unavailable in v2.1.x and pointing users to the supported ReplacePrefixMatch and ReplaceFullPath alternatives. Also removed the corresponding TrafficPolicy cleanup command.

Fixes kgateway-dev/kgateway#13452

Change Type

/kind documentation

Additional Notes

Only the 2.1.x version of the page is affected. The 2.2.x and latest pages are correct and unchanged.

[anvithagowda098]

Instead of duplicating the entire assets/docs/pages/traffic-management/rewrite/path.md, I'm trying to keep the shared assets template intact and use {{< version exclude-if="2.1.x" >}} to hide the Regex rewrite section on 2.1.x.

But the problem is that Hugo loses heading rendering for ##/### headings inside version blocks that contain nested shortcodes so wrapping the whole thing breaks things. I also checked the repo and couldn't find an existing example of an entire ## section being hidden this way.

Would extracting the regex rewrite content into assets/docs/snippets/regex-rewrite.md and calling {{< reuse >}} inside the exclude-if block work here? Or is there a preferred pattern for this?

@artberger @kristin-kronstain-brown

[kristin-kronstain-brown]

@anvithagowda098 Have you tried changing {{< version exclude-if="2.1.x" >}} to {{% version exclude-if="2.1.x" %}} yet? That seems to help with those kind of rendering issues sometimes.

[anvithagowda098]

@kristin-kronstain-brown does not work either. Extracting the regex rewrite content into snippet breaks as well. Appears to me as if the current PR is the right solution.

[kristin-kronstain-brown]

@anvithagowda098 Thanks for tracking this down. Yeah, the version shortcodes can be tricky. I've been working on trying to get that working better, but for this instance, I think it's fine to go without them and just copy over the content. It's an older version and the later versions do still use the shared asset file. As I was starting to go through the shared topic for comparison, I noticed some issues with that one. Can you make sure your version corrects the same things I did in the asset file for the other versions?
https://github.com/kgateway-dev/kgateway.dev/pull/835/files

[anvithagowda098]

@kristin-kronstain-brown made the necessary changes!