[FEAT] extends in design components should be included in API docs.

[xelaint]

💡 Feature request

Feature Name

extends in design components should be included in API docs.

The Desired Behavior

i,e. in Button, DaffButtonBaseDirective should be included in API docs.

Your Use Case

Prior Work

Environment

Daffodil version: X.Y.Z
Angular version: X.Y.Z 

 
For Tooling issues:
- Node version: XX  
- Platform:  

Others: