vertico: add variable to set company completion styles

modules/completion/vertico/autoload/vertico.el

@@ -10,7 +10,7 @@
 orderless."
   :around 'company-capf--candidates
   (let ((orderless-match-faces [completions-common-part])
-        (completion-styles '(basic partial-completion orderless)))
+        (completion-styles +vertico-company-completion-styles))
     (apply fn args)))
 
 ;;;###autoload

modules/completion/vertico/config.el

@@ -1,5 +1,12 @@
 ;;; completion/vertico/config.el -*- lexical-binding: t; -*-
 
+(defvar +vertico-company-completion-styles '(basic partial-completion orderless)
+  "Completion styles for company to use.
+
+The completion/vertico module uses the orderless completion style by default,
+but this returns too broad a candidate set for company completion. This
+variable overrides `completion-styles' during company completion sessions.")
+
 (use-package! vertico
   :hook (doom-first-input . vertico-mode)
   :config