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.

modules/editor/siren-fussy.el

@@ -0,0 +1,42 @@
+;;; siren-fussy.el --- jimeh's Emacs Siren: fussy configuration.
+
+;;; Commentary:
+
+;; Basic configuration for fussy.
+
+;;; Code:
+
+(use-package fussy
+  :ensure t
+  :custom
+  (completion-category-overrides nil)
+  (completion-ignore-case t)
+  (pcomplete-ignore-case t)
+
+  (fussy-ignore-case t)
+  (fussy-filter-fn 'fussy-filter-orderless-flex)
+  (fussy-score-fn 'fussy-fzf-native-score)
+
+  :preface
+  (defun siren-fussy--company-transform-advice (f &rest args)
+    "Manage `company-transformers'."
+    (let ((company-transformers '(fussy-company-sort-by-completion-score)))
+      (apply f args)))
+
+  :config
+  (add-to-list 'completion-styles 'fussy)
+  (advice-add 'company--transform-candidates
+              :around 'siren-fussy--company-transform-advice)
+  (setq completion-category-defaults nil))
+
+(use-package orderless
+  :commands (orderless-filter))
+
+(use-package fzf-native
+  :straight (fzf-native :repo "dangduc/fzf-native" :host github
+                        :files (:defaults "bin"))
+  :config
+  (fzf-native-load-dyn))
+
+(provide 'siren-fussy)
+;;; siren-fussy.el ends here