Backport of docs: add note about path prefix matching behavior for HTTPRoute config into release/1.16.x

[hc-github-team-consul-core]

Backport

This PR is auto-generated from #17860 to be assessed for backporting due to the inclusion of the label backport/1.16.

The below text is copied from the body of the original PR.

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Description

The Gateway API spec says the following about path prefix route matches (source):

Matches based on a URL path prefix split by /. Matching is case sensitive and done on a path element by element basis. A path element refers to the list of labels in the path split by the / separator. When specified, a trailing / is ignored.

For example, the paths /abc, /abc/, and /abc/def would all match the prefix /abc, but the path /abcd would not.

Consul API Gateway does simple string prefix comparison today, which is the same thing that the rest of Consul does. The result is that, contrary to the specification above, we do match /abcd. This is because Consul uses RouteMatch_Prefix across the board for prefix matching when generating xDS instead of RouteMatch_PathSeparatedPrefix.

This PR just calls out that difference in the docs so we don't surprise anyone as much as we can help it.

Testing & Reproduction steps

N/A

Links

Vercel preview of added note

PR Checklist

• updated test coverage
• external facing docs updated
• appropriate backport labels added
• not a security concern

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Overview of commits

• 64f6ad3 - 7cd1e75

[github-team-consul-core-pr-approver]

Auto approved Consul Bot automated PR