kde plot `'y'` argument ends up being 'x' label - rename it to `columns`?

#### ALL software version info

pandas: 2.1.4
hvplot: 0.9.1

#### Description of expected behavior and the observed behavior

The `'y'` argument determines which column(s) to compute distributions of.

It's a bit counter-intuitive, then, that the x-label ends up being the `y` argument

Don't know what the simplest solution is - rename `y` for this plot, perhaps to `columns`?

#### Complete, minimal, self-contained example code that reproduces the issue

```
df = pd.DataFrame({'a': [2,4,2,5,6,7,3,6,7]})
df.hvplot.kde(y='a')
```

#### Stack traceback and/or browser JavaScript console output

#### Screenshots or screencasts of the bug in action


- [x] I may be interested in making a pull request to address this