Modal close button - Bootstrap 5.2x support

[HarpunDK]

Button-close are rendered incorrect.

For Bootstrap 5.2x support, the following should be correct:
templates.closeButton value: '<button type="button" class="btn-close bootbox-close-button close" aria-hidden="true"></button>',
Bootbox.js (l:94-95)

Instead of: '<button type="button" class="bootbox-close-button close" aria-hidden="true">&times;</button>,'

This issue also exists in 5.1x i think.

Let me know if I should create a Pull request. Dont know if compatibility issues with lower versions of Bootstrap, how these are handled.

Thank you for a very nice library

[tiesont]

This has been discussed before. For example, in #777

If you need Bootstrap 5 support, the closest available is the v6-wip branch, which seems to work, but I am still not quite ready to push that to master yet.