Describe the problem

Hi everyone and first of all thanks for this wonderful sphinx theme 👏

The behavior of the "use_edit_page_button" is not working as expected.
Since my repository is hosted by my company in a dedicated GitHub Enterprise, the base URL is not https://github.com/ but https://github.my-compagny.com/

bellow are my html_theme_option:

html_theme_options = {
    "repository_url": "path/to/my/repo",
    "use_repository_button": True,
    "use_issues_button": True,
    "use_edit_page_button": True,
}

Both use_repository_button and use_issues_button works perfectly well.
However the edit button point to the standard https://github.com/ (and so return a 404 error).

Steps to reproduce

As said above the issue occurs because my repository is hosted on a GitHub Enterprise.
So I cannot provide you a step to reproduce the issue.

However I think that using the repository_url as base for the use_edit_page_button should fix the issue.

The version of Python you're using

python version: 3.8.8

Your operating system

Windows 10

Versions of your packages

sphinx-book-theme==0.1.6