Added examples for azimuthal and longitudinal properties in 3D and 4D

[pandyah5]

Description

This PR adds descriptive example to the following properties in /src/vector/backends/numpy.py (Mentioned in #503)

• Azimuthal - 3D
• Azimuthal - 4D
• Longitudinal - 3D
• Longitudinal - 4D

The demo examples have been run and verified.

Checklist

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't any other open Pull Requests for the required change?
• Does your submission pass pre-commit? ($ pre-commit run --all-files or $ nox -s lint)
• Does your submission pass tests? ($ pytest or $ nox -s tests)
• Does the documentation build with your changes? ($ cd docs; make clean; make html or $ nox -s docs)
• Does your submission pass the doctests? ($ pytest --doctest-plus src/vector/ or $ nox -s doctests)

Before Merging

• Summarize the commit messages into a brief review of the Pull request.

[Saransh-cpp]

Amazing, thanks for picking this up, @pandyah5! A few suggestions below -

[pandyah5]

Thanks for the feedback @Saransh-cpp! I have addressed all the comments

[Saransh-cpp]

To maintain uniformity

[Saransh-cpp]

Thanks for the amazing work, @pandyah5!