Adding support for hash linked slideNumber

[sean-parent]

There are two changes here -

Make the hash slide numbering match the shown slide so that slide.html#/3 is slide 3 and not slide 2.

Added an href link to the slide number if shown to make it simple to share a link to a particular slide even when history is not enabled. This also makes it easy to lock to a particular slide when using auto refresh tools while developing.

[mschilli87]

This was suggested before but decided against: #2067

[sean-parent]

Recommendations to proceed?
I could make 1 based hash indexing optional
I could drop 1 based hash indexing and just keep the href link in the slide number
I could make the href link in the slide number optional
Other suggestions?

[hakimel]

I think it'd be best to make the 1-based indexing optional to avoid breaking existing content. If you can revise that I'd be happy to merge this in. Thanks!

[sean-parent]

One based indexing is now optional (defaults to zero based for compatibility)

[hakimel]

Thanks for updating. One more thing, can you change the merge target of the PR to the 'dev' branch? That's the working branch, we merge dev into master when a new version goes out.

[marcosalpereira]

There is still something preventing the incorporation of this change?

[mschilli87]

@hakimel: If it's just the wrong target branch, you should be able to change that yourself:
https://blog.github.com/2016-08-15-change-the-base-branch-of-a-pull-request/

[sean-parent]

Merged to dev branch and resolved conflicts.

[hakimel]

Thanks for resolving the conflicts 🙌