Make a usage example in the docstring

[cmp0xff]

I think it is a bit easier for our future selves if we have have a usage example in the docstring.
Something like

hamilflow/hamilflow/models/harmonic_oscillator.py

Lines 141 to 151 in 04ea13c

	To use this generator,
	```python
	params = {"omega": omega}
	ho = SimpleHarmonicOscillator(params=params)
	df = ho(n_periods=1, n_samples_per_period=10)
	```
	`df` will be a pandas dataframe with two columns: `t` and `x`.

Ursprünglich gepostet von @emptymalei in #58 (comment)

[cmp0xff]

I think the docstrings of the classes are too long.

• The description of the initialising parameters can be moved to the initialisers.
• The example can go to __call__.
• We can make referring links between docstrings, like https://github.com/matplotlib/matplotlib/blob/1b082070115e0c82082f560b0cc4c728357bfd7e/lib/matplotlib/axes/_axes.py#L86, where all syntaxes in `` are links referring to other docs, see https://matplotlib.org/stable/api/_as_gen/matplotlib.axes.Axes.html#matplotlib.axes.Axes for the results.

Unfortunately I did not find a documentation for how the syntaxes are rendered in matplotlib. However we do not need to make things too complicated for us, either.

What do you think @emptymalei ?