a few things that can be improved in the reference documentation

• Similar to "Namespace", there should be an "Implements" in the docs template when a class implements an interface (for example, the ServiceAccountCredentials should link to FetchAuthTokenInterface)
• The interfaces are not being linked in the ClientOptions array parameters
• The interface isn't linked in the ClientOptions description either, but that might be due to the interface page being new - we should wait until the next release docs are built to verify.