Group parsing are not supported

[lprobsth]

Is your feature request related to a problem? Please describe.
Doxygen supports grouping of functions and variables, so they can share common descriptions or simply can be categorized.
The syntax is described here: https://www.doxygen.nl/manual/grouping.html

Right now this extension does not support autogenerating the grouping tags - which is reasonable. (#255 proposes adding autocomplete for the grouping tag - but it is not implemented).

But if a user adds groups by hand, the groups properties are not parsed and therefore are not available in the preview of the function or variable description in vscode.

Describe the solution you'd like
When hovering over a function or variable the groups properties should be displayed.

Describe alternatives you've considered
Adding a doxygen block for each function. But if a group has many functions or variables this quickly clutters the files and properties can not be quickly adapted if something changes.