Suggest article creation for topics that don't exist

In previous updates we added insane topic links which allow you to write #mathematics to link to OurBigBook Web topics such as: ourbigbook.com/go/topic/mathematics

The outcome of that however is that it is also easy and correct to create links to topics that don't yet exist on the OurBigBook Web instance.

To make this nicer, we've unconsciously copied Wikipedia once again, and added a "Create an article for this topic" link

For example, currently OurBigBook.com the topic "Endoplasmatic Reticulum" does not have any articles on it. So if you created a link <#endoplasmatic reticulum>, it would redirect you to: ourbigbook.com/go/topic/endoplasmic-reticulum

Previously, this would show "Topic does not exist". But now it shows a button that opens the new article editor with pre-filled title "Endoplasmatic reticulum". The title choice is only a heuristic as it can't know the correct capitalization, but it covers most cases corectly by default and can be modified manually as needed.