Is it possible to customize links after the fact?

For example, when auto-linking blob regexes it looks like this produces:

<a href="&#x26;nBmGtTlQew5bSiy5CwKA7Qz6Qfj6UYzmf9gYgcNg+90=.sha256">&#x26;nBmGtTlQew5bSiy5CwKA7Qz6Qfj6UYzmf9gYgcNg+90=.sha256</a></p>

For example, it would be great if this could take an optional callback which let you modify the link after it's parsed with the regex. Or maybe there's an easier way to go about this?