Improve the file action buttons on a commit

Description

When viewing a file on a specific commit/tag/whatever (not on a branch), the file action buttons (open in GitHub desktop, edit and delete) have tooltips “You must be on a branch to *”, however they are not disabled but pointing to the login page along with a redirect to the same page, which is quite confusing:

https://github.com/sindresorhus/refined-github/blob/3775e52/source/features/useful-not-found-page.tsx
⬇️
https://github.com/login?return_to=https%3A%2F%2Fgithub.com%2Fsindresorhus%2Frefined-github%2Fblob%2F3775e52%2Fsource%2Ffeatures%2Fuseful-not-found-page.tsx

I suppose we can improve the buttons a bit:

• One option is to disable them entirely. GitHub does put a .disabled class but that doesn’t invalidate the links.
• Another option is to have these buttons work like if we are on the default branch, maybe with a prompt “Do you want to take this action on the default branch?”
• Make them work like default-branch-button or just point the user to default-branch-button, something like that.

Screenshot

Example URL

https://github.com/sindresorhus/refined-github/blob/3775e52/source/features/useful-not-found-page.tsx

[kidonng]

The “disabled” buttons are now correctly grayed out. Maybe it’s not worth fixing it given default-branch-button is present…

[kidonng]

That makes sense. The intention is to simplify the following steps to one click:

1. Click “View file”
2. Click default-branch-button
3. Click edit button

If the original request in this issue is resolved, the second step can be saved.