Remove the fuzzy matching variable introduced in #289. The rationale is
addressed in
https://github.com/jethrokuan/org-roam/issues/514#issuecomment-619438401:
Helm, Ido and Ivy have their own mechanisms for fuzzy search, and can be
tweaked using their own configuration options outside of org-roam, e.g.
through `ivy-re-builders-alist`.