Add support for custom server error response handlers

[dabico]

I started integrating this library into my projects (phenomenal work by the way), but I noticed that there is no way of specifying custom error handlers when fetch fails:

https://github.com/lekoala/bootstrap5-autocomplete/blob/a1feee07c7d4241234802aa357b06f43936bf703/autocomplete.js#L1236-L1242

It would be nice if we had an error-handling equivalent to onServerResponse (i.e. onServerUnreachable or onFailedFetch), as onAfterFetch does not provide access to the returned Promise.

[lekoala]

hi @dabico thanks for the kind words it's really easy to add, it's on master now https://github.com/lekoala/bootstrap5-autocomplete/commit/4055369a6adb50e62637a1a10da3415c9ebc25e7 it's cleaner to have it configurable anyway :)

[dabico]

Wonderful! Patiently waiting for the next release 😄

[lekoala]

done :)