Bazel-flag-bot should link to buildifier auto fix where applicable

[ittaiz]

Buildifier has the option to automatically fix some incompatible flags.
It can be very useful to have the issue opened by the bazel-flag-bot tool link to this so that rule owners don't have to manually do what a tool knows how to do.
For example we (rules_scala) got this issue about loading rules_java and I completely deferred it because of the hassle. If I had an explanation and a link to the auto fix I would probably have deferred it less.

Seeing as I'm lazy but responsible (and also have been in many community discussions) I remembered there was a thought to automate this stuff so I asked on the relevant issue and thankfully got a helpful reply (thanks @iirina). This might not be the case for others.