ENH additional error codes, tidy translations

[andrewandante]

Fixes #78

Adds in 418 and a few others (source: https://en.wikipedia.org/wiki/List_of_HTTP_status_codes#4xx_client_errors and https://en.wikipedia.org/wiki/List_of_HTTP_status_codes#5xx_server_errors)

Cleaned up a couple of en translations that still referenced Base Pages

[GuySartorelli]

Seems sensible, thank you!
I'm not a fan of the "I'm a teapot" error being treated as a "real" error myself, and agree with Max on the original issue that this is likely to confuse content editors... but ultimately it sounds like the consensus is that since it's in the spec it should be included. That's hard to argue against, so I'll accept that it's there.

Will merge on green.

[andrewandante]

Thanks :) My thought while doing this was to make the list of codes configurable somehow, but it started to feel unwieldy pretty quickly so I settled on this one.

Perhaps I'll create a separate issue that makes the list of codes to provide to the drop down configurable in yaml? Then limits it to something like 400, 401, 403, 404, 500, 503, 504 as a baseline?

[GuySartorelli]

Perhaps I'll create a separate issue that makes the list of codes to provide to the drop down configurable in yaml? Then limits it to something like 400, 401, 403, 404, 500, 503, 504 as a baseline?

Sounds like a good issue. I probably wouldn't limit it by default (some people might consider that a breaking change... it's a grey area as to whether it would be or not) - rather I'd include the full list in the default set, and developers can choose to hide any they want to by setting them to null

e.g. if it was defined as

private static array $error_codes = [
  '404' => 'not found'
  // etc
];

Then developers could add this to their yaml

SilverStripe\ErrorPage\ErrorPage:
  error_codes:
    418: null

Or perhaps have a separate disallowed_error_codes config? Or a allowed_error_codes config that is null by default but if it's an array, it overrides the default full set?

Anyway, all that to say "yes, please create an issue about it" - we can discuss implementation in that issue.