[FEATURE] Option for steps in ratio panel in addition to dots

[JaLuka98]

Describe the problem, if any, that your feature request is related to

In the bottom panel of ratio plots, black dots are always drawn, leaving no flexibility for user choices, such as a "step ratio" with a piecewise continuous function and associated error bars per bin.
See

hist/src/hist/plot.py

Line 435 in cdfc4c3

_ratio_points = ax.scatter(x_values, ratio, color="black")

for the relevant section in the code (plot_ratio_array).

Describe the feature you'd like

Possibility for a step line in the ratio panel in addition to the default scatter points.
Point of attack would be

hist/src/hist/plot.py

Line 435 in cdfc4c3

_ratio_points = ax.scatter(x_values, ratio, color="black")

.
Proposing an additional argument to handle this. Can be passed as part of rp_kwargs.

Describe alternatives, if any, you've considered

No alternatives that respect the current structure of plot_ratio_arrays come to mind because the formatting of the ratio plot is "hardcoded" in that function.

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Can you let me know if you find this reasonable? I could try to implement this myself and check how it works.