Recent hotfix made `sns.relplot` incompatible with latex plotting.

Hi, and first of all thanks for the great library!

I have discovered a problem with a recent hotfix (this line) and latex plotting.

Concretely, the hotfix prepends underscores to all plot variables, e.g. turning x into_x and only changes the labels later. This causes a problem with the FacetGrid underlying relplot, which calls tight_layout here.

For some reason, this causes matplotlib to render the plot with the axis labels including underscores. I believe it happens to find margins, but I am not sure. In any case, the latex render cannot handle the underscores and crashes.

Affected versions

0.11.2 only; version 0.11.1 (without the hotfix) works fine.

Steps to reproduce

import seaborn as sns
import matplotlib as mpl
import pandas as pd
mpl.rcParams.update({
        'text.usetex': True,
})

testdata = pd.DataFrame({'x': [1, 2], 'y': [2, 3]})
sns.relplot(data=testdata, x='x', y='y');

This raises:

RuntimeError: latex was not able to process the following string:
b'_x'

Possible fixes

Prepend with something more latex friendly instead of underscores, e.g. temp or anything.

[mwaskom]

I believe this was handled upstream: https://github.com/matplotlib/matplotlib/pull/20706

[NotSpecial]

Great news! I can confirm that it works for me again as well with matplotlib version 3.5.1 and seaborn version 0.11.2. Thanks for checking up on this.