Italic format not handled

### Description of the modifications

At the moment, italic formatting is not handled. This needs to be enhanced in the future.

Mentioned in https://github.com/ansys/pymapdl/pull/3892/files/3d97e2f514b17ea6d143995d32ec52a02cfc43b3#r2075101678.

### Useful links and references

Visible in:
- [ ] [atan](https://cautious-adventure-g6vqq8v.pages.github.io/version/dev/post26/_autosummary/ansys.mapdl.core._commands.post26.operations.Operations.atan.html#ansys.mapdl.core._commands.post26.operations.Operations.atan)

Start with the generated atan documentation linked in the issue and review the referenced comment in pull request 3892 to understand how italic formatting appears. Trace the XML-to-Python documentation conversion path and identify the relevant tests or fixtures; done means italic source text is represented correctly in the generated Sphinx documentation.

Written by the indexing model from the issue text.