Feature Request: Support Backlinks with [[]] style

Editors such as Obsidian support backlinks, links between files, using square brackets. Support for this feature in HackMd would provide an excellent tool for the community while improving compatibility with other editors that may be used to edit the same files.
Many markdown tools are getting requests to support backlinks.

This could be implemented by
- just allowing creation of and interpreting a link in the style of [[Name of File]]
- and could then possibly be expanded with features such as a list of files that link TO the current file and a list of files linked FROM the current file, possibly placed in the same area as the content, e.g. underneath.

Another feature that could be implemented is the remaining syntax that Obsidian uses,
- allowing the backlink to link directly to a heading or section or to be renamed, e.g. [[The File Name#This Heading|Display Name]] or [[The File Name^aSection|Display Name]].