Feature summary (what you would like to be able to do and where):
Currently, in Android Wikipedia app, when viewing a talk page, there are no way to go to the corresponding article/project/template/other namespaces either.
Such button should be added to make discussing article issues easier in the app.

Use case(s) (list the steps that you performed to discover that problem, and describe the actual underlying problem which you want to solve. Do not describe only a solution):
Like when try to refer to article content when replying in a talk page.

Benefits (why should this be implemented?):
Users will no longer need to use another browser to refer to article content while replying to talk page messages.