Convert all docstrings to numpy-style format

[jobovy]

With the help of GitHub Copilot using the following prompt

Replace just this docstring with a numpy style docstring; Make entries in the HISTORY section into a bullet-pointed Notes section with bullet points with exactly the same text and formatting (including starting with year-month-day) as each line in the HISTORY section; make sure to keep indentation the same as before and only change the docstring. Replace, don't add. Don’t add types. Leave the function signature alone.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (2c77613) 99.92% compared to head (44e0980) 99.92%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #608   +/-   ##
=======================================
  Coverage   99.92%   99.92%           
=======================================
  Files         198      198           
  Lines       29173    29175    +2     
=======================================
+ Hits        29150    29152    +2     
  Misses         23       23           

Files	Coverage Δ
galpy/actionAngle/actionAngle.py	100.00% <ø> (ø)
galpy/actionAngle/actionAngleAdiabatic.py	100.00% <ø> (ø)
galpy/actionAngle/actionAngleAdiabaticGrid.py	99.35% <ø> (ø)
galpy/actionAngle/actionAngleAdiabatic_c.py	100.00% <ø> (ø)
galpy/actionAngle/actionAngleHarmonic.py	100.00% <ø> (ø)
galpy/actionAngle/actionAngleHarmonicInverse.py	100.00% <ø> (ø)
galpy/actionAngle/actionAngleInverse.py	100.00% <ø> (ø)
galpy/actionAngle/actionAngleIsochrone.py	100.00% <ø> (ø)
galpy/actionAngle/actionAngleIsochroneApprox.py	100.00% <ø> (ø)
galpy/actionAngle/actionAngleIsochroneInverse.py	100.00% <ø> (ø)
... and 103 more

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