Ensure that button.btn and a.btn have the same cursor

[md5]

This PR adds the cursor: default property to the .btn class to ensure that button.btn and a.btn have matching cursor behavior. It also adds cursor: pointer to .btn-link. I believe this aligns with the intent of 232e86d (added as part of #21439).

[ghost]

It would be better to set cursor: pointer to both elements.

[md5]

@lucascono cursor: pointer was purposely removed from .btn in 232e86d. This PR is only attempting to ensure that the intent of that commit is implemented consistently.

[ghost]

Hello @md5 :

I have read the article and understand the point. First of all I thank you for answering. However, just by habit, I think a bad decision. From the technical point of view I understand the reasons, but considering what the common user usually uses, I think cursor: pointer is better.

In the same article published by Adam Silver, in the comments, the "Bookmark this story to read later" icon is a button and has cursor: pointer. On the same page that promotes the opposite.

Obviously I consider that the decision of the authors of Bootstrap is already taken. However, I did not want to stop giving my opinion and say that, at least in my future projects with v4, this will be the first thing I have to change forever. Beyond what Adam Silver says, I think this has been a very bad decision. But as I said before, it's just my opinion.

Thanks again for responding and for collaborating with such a nice project. Greetings from Argentina (sorry for my english).

[md5]

I've rebased this to fix a conflict with the changes in cd22eb1

[md5]

@mdo Is this change something you'd like to accept for Bootstrap v4? If not, I'd like to close the PR.

[XhmikosR]

Closing in favor of #27021