daml-doc improvement: show full interface/template name in interface instances

[akrmn]

Use the interface name instead of type synonyms in interface instances:

It is common to use a qualified type synonym I for interfaces. For instance:

import Daml.Finance.Interface.Asset.Instrument qualified as Instrument (I)
import Daml.Finance.Interface.Common.Disclosure qualified as Disclosure (I)

template X ...
  interface instance Disclosure.I for X where ...
  interface instance Instrument.I for X where ...

In the generated documentation for template X, we see

• interface instance I for X
• interface instance I for X

instead of

• interface instance Instrument for X
• interface instance Disclosure for X

which makes it harder to read (as we are forced to click on I to understand what I refers to.

(spun off from https://github.com/digital-asset/daml/issues/14694)