Fix and update GenX documentation

[RuaridhMacd]

Description

This fixes the issue with DOLPHYN not properly pulling the GenX documentation.

The issue was that while GitHub sees GenX as a submodule, DOLPHYN sees GenX as part of its own code - not a module. This was set up this way to make it easier to overwrite code and avoid the need to export more functions.

Some problems remain. We'll create separate issue to address theseL

• Some warnings still exist when compiling the documentation, due to incorrect markdown formatting in the doc strings.
• Some GenX functions are missing documentation, which creates warnings
• Some functions with docstrings are not being included in the documentation.

Fixes issue #

#180

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

n / a

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have run tests with my code to avoid compatibility issues
• Any dependent changes have been merged and published in downstream modules