Information about typealiases used in signatures should be preserved and available for the user.

[Kordyjan]

Right now, dokka is displaying types in signatures how the compiler sees them, so all type aliases are expanded to the real types. It may be unintuitive behavior for many users, that their aliases are not shown in signatures.

The goal of this task is to preserve information about aliases and later display it to the users, preferably in such a way that they can see and copy both real type and alias type, depending on their needs.

This task includes:

• obtaining information about alias and saving them in the model (as Bound extra property or, preferably, as new Bound subclass)
• changing the signature provider in such a way, that information about an alias is passed to the frontend
• providing frontend representation for both types in html format
• ensuring that markdown formats only show information about alias type (right now they only show real type)
• ensuring that kotlin-as-java and Javadoc only shows real type (it is already a case but we don't want to break it)
• creating tests for generated ContentNodes (both standard and Javadoc), html and markdown outputs

If needed, smaller sub-tasks can be extracted from this one.

[Kordyjan]

Proposal of frontend representation: Of course, the magnifying glass icon is only a placeholder. After clicking it the aliases should be expanded, so users can click links, select text and use copy button.