Add example to basis_frequencies

[arobinson905]

Description of the feature

Add an example to basis_frequencies to help the user

Steps for implementing the feature

from pyaedt import Hfss
from pyaedt.modules.SetupTemplates import SweepHFSS

hfss = Hfss(specified_version=version, projectname=proj, designname=gtemDesign, solution_type=solutiontype, setup_name=setupname, non_graphical=False, new_desktop_session=False, close_on_exit=False, student_version=False, machine='', port=0, aedt_process_id=None)
hfsssetup = hfss.setups[0]
hfssSweep = SweepHFSS(hfsssetup, "Setup1", 'Sweep', sweeptype ='Interpolating', props=None)
freqsweep = hfssSweep.basis_frequencies

Useful links and references

No response

[arobinson905]

also, basis_frequencies returns Hz, unlike frequencies, which returns GHz. This should be noted in the documentation (or ideally changed so both functions return the same units)