docs: add RouteConditionReason to v1alpha2 docs, enumerate possible reasons for each RouteConditionType #1109
Description
What would you like to be added:
A section to the API Specification for RouteConditionReason, mirroring similar content from ListenerConditionReason
Why this is needed:
Only RouteConditionType is currently documented, and it does not offer sufficient clarity on what reasons are allowed for each condition type, and when those reasons should be used.