Making a subplot figure with umap.plot objects

I know that umap.plot return matplotlib.pyplot axes but I cannot get my head around making a subplot (as in a 2D array of `umap.plot`s)

I am trying:

```python
import matplotlib.pyplot as plt
import umap.plot
import umap
import sklearn.datasets

pendigits = sklearn.datasets.load_digits()

fig, axs = plt.subplots(2,2,figsize = (10,10))
for r in range(1):
for c in range(1):
mapper = umap.UMAP(n_neighbors = ((r+c) + 1)*5, spread = ((r+c)+1)*2).fit(pendigits.data)
axs[r,c] = umap.plot.points(mapper, labels = pendigits.target)

plt.show()
fig.savefig('fig.png')
```

I am simply getting one `umap.plot` and an empty 2x2 grid, what am I doing wrong?

Start with the provided matplotlib.pyplot subplots loop and the umap.plot.points call; inspect how the plotting entry point uses axes and compare that with the axs[r,c] array. Reproduce the 2x2 example, then verify that every subplot is populated and that the saved figure contains all panels.

Written by the indexing model from the issue text.