BUG: `Styler.hide_columns()` does not hide index name row
Whilst `Styler.hide_index()` hides column header name (along with the index), the index name row persists when `Styler.hide_columns()` is used to hide column headers.

The index names rows should also be hidden, since currently there is no way to hide it independently.

What to do:

1) Find `pandas/io/formats/style_render.py`
2) Find the method for the `StyleRenderer` called `_translate_header` and read the documentation what it is trying to structure.
3) Go to the section in the method labelled `# 2` and insert `self.hide_columns_` into the conditional.
4) Add a test to `pandas/tests/io/formats/style/test_style.py` that addresses this.
