docs(openapi): add spec for arrivals-and-departures-for-location endpoint

[3rabiii]

Description

This PR adds the missing OpenAPI specification for the arrivals-and-departures-for-location endpoint.

While reviewing the legacy Java documentation and codebase (ArrivalsAndDeparturesForLocationAction) for API parity, I noticed this endpoint was missing from the openapi.yml spec. This PR ensures the spec accurately reflects the legacy behavior and the upcoming Go implementation.

Changes Made

• Added the /api/where/arrivals-and-departures-for-location.json path.
• Included all supported query parameters to ensure 100% API parity (including optional parameters like latSpan, lonSpan, time, routeType, and emptyReturnsNotFound).
• Added the ArrivalsDeparturesForLocationResponse schema in the components/schemas section to accurately reflect the nested response structure (using entry with stopIds, arrivalsAndDepartures, and nearbyStopIds).

Related Issues/PRs

#787
@aaronbrethorst

[3rabiii]

Marking this as a draft for now.
The check-openapi CI job failed because I realized the OpenAPI spec (testdata/openapi.yml) must be updated in the upstream OneBusAway/sdk-config repository first

[ARCoder181105]

Hey @3rabiii ,

Good catch... If possible can you make this PR as a follow-up of #787 , as this endpoint handler is implement in that PR...

Just add a follow-up line in the desc..

[3rabiii]

Ok, I originally linked it to the base openapi.yml PR, but no problem! I just edited it to link to your PR that creates this endpoint.