DOC: Remove storage options from doc of Styler.to_excel
Remove parameter from doc string that is not in function.  `Styler.to_excel` only supports `storage_options` in 1.5.x+

The PR is only for the 1.4.x branch.
Not sure if there is an easy fix for this.  Getting a double line break issues since I think omitting the storage options added a line break. You need to remove the import of `_shared_docs` which is now unused.

The way this was originally implemented seems a bit cumbersome, but one problem seems to be the version added, which expect `storage_options` to not be empty as it is. What I'd do is:

- Remove the `.. versionadded:: ...` from the original docstring (NDFrame.to_excel docstring)
- Add it to the storage parameter injected with `doc`, something like `storage_options=_shared_docs["storage_options"] + '  ..versionadded:: ...'`

If too many blank lines exist in that block after this (I don't think it'll happen), you can remove them from the docstring with `{storage_options}\` and add them to the injected values if any misses them. This pull request is stale because it has been open for thirty days with no activity. Please [update](https://pandas.pydata.org/pandas-docs/stable/development/contributing.html#updating-your-pull-request) and respond to this comment if you're still interested in working on this. I think we can close this? There is currently no release planned for the 1.4.x branch Makes sense. 