Fixing inconsistency in example

[chbauman]

The example code is described as "This is an example of how to use the Test5 class", but actually the class "Test7" was used in the example code.

[jakobandersen]

• Can you rebase this on top of master? That should clear up some of the CI errors.
• Do you remember where in the documentation this was? I can't immediately find it.

[chbauman]

The example is at: https://breathe.readthedocs.io/en/latest/doxygen.html#example, it shows the code in the file: https://github.com/chbauman/breathe/blob/master/examples/doxygen/example.cpp

[jakobandersen]

Thanks!