feat(completion): replace orderless with fussy

Use fussy instead of orderless for filtering and scoring/ordering
completion candidates. This seems to overall order results in a much
better way than just orderless.

Technically orderless is still used to filter the candidate list, but
fzf-native is used to score/order the results.

core/siren-core-modules.el

@@ -52,7 +52,7 @@
 
 ;; Completion Systems and Interfaces
 (require 'siren-vertico)
-(require 'siren-orderless)
+(require 'siren-fussy)
 
 ;; Linting
 (require 'siren-flycheck)