Collapse all backlinks, improved Chinese char support, link to txt files, all suggestions for empty # or [[

Fixes:

• #117 - add collapse all button to backlinks view - tx @MCluck90
• #119 - improve tag recognition, Chinese character support using \p{L} instead of \w - tx @thomaskoppelaar, @frankreporting. Closes #114, #115.
• upgrade jest deps to resolve depandabot alerts
• #122 - return all suggestions on 'empty' # and [[. Closes #99.
• #123 - allow linking to txt files - tx @thomaskoppelaar. Closes #107.

Diff:

https://github.com/kortina/vscode-markdown-notes/compare/311dda9..b7660f