[BUG] Binning misalignment using `plot_ratio` with `Int` axes

[GuillermoFidalgo]

Describe the bug

I have two histograms with the same axes ( a dataset axis that is StrCategory, a channel axes that is also StrCategory and an Njet axis defined as)

njet_axis = hist.axis.Integer(4,15, name = 'njet', label='Jet multiplicity')

All is well and good most of the time with other axes but when trying to make a ratio plot for something like Data/MC with Interger axes it is not aligning the ratio plot points correctly with the bins on the regular plot above it. I don't understand why it's apparently not aligning the ratios on the lower axes as I would expect.

Steps to reproduce

A MWE is given below.
Running code below shows that the issues seems to be related with Int axes

import hist
import matplotlib.pyplot as plt

d = [1,
     2,2,
     3,3,3,
     4,4,4,4,
     5,5,5,5,5]*10_000

d2 = [1,1,1,1,1,
      2,2,2,2,
      3,3,3,
      4,4,
      5]*10_000

temp_H_Int = hist.new.Int(1,6,name= 'Int').Double().fill(d)
temp_H2_Int = hist.new.Int(1,6,name= 'Int').Double().fill(d2)

temp_H_Var = hist.new.Var([1,2,3,4,5,6],name= 'Var').Double().fill(d)
temp_H2_Var = hist.new.Var([1,2,3,4,5,6],name= 'Var').Double().fill(d2)

# Compare the plots (These are seen to be identical, as expected)
fig,ax = plt.subplots(1,2,figsize = [15,5])
temp_H_Int.plot(ax=ax[0])
temp_H2_Int.plot(ax=ax[0])


temp_H_Var.plot(ax=ax[1])
temp_H2_Var.plot(ax=ax[1])
plt.show()

Now look at the ratio plots code in 2 different cells

# Ratio Plots appear to be aligned differently with the bins wrt previous plots
temp_H_Int.plot_ratio(temp_H2_Int,
                      rp_num_label="H Int",
                      rp_denom_label="H2 Int",
                      rp_ylabel='H/H2',
                      rp_uncert_draw_type="line")

# This one produces the expected alignment 
temp_H_Var.plot_ratio(temp_H2_Var,
                      rp_num_label="H Var",
                      rp_denom_label="H2 Var",
                      rp_ylabel='H/H2',
                      rp_uncert_draw_type="line")

[alexander-held]

I suspect this might be working as intended: for the integer axis the integers themselves are the categories and the bins are centered on them. For the variable width bins (or also fixed width bins), the bins are centered around the bin centers instead.

[GuillermoFidalgo]

After further consideration this seems to be an actual bug.