cf-matthias

See: SPM-2140 SHIP-7949

CUSTESC-59217 - Add cache.match 504 to general 502/504 errors page

1

### Summary 502/504 general errors page didn't mention 504s from Cache API cache.match operations. ### Documentation checklist - [X] The change adheres to the [documentation style guide](https://developers.cloudflare.com/style-guide/).