Add value+docstring columns to doom/help-custom-variable

When used with ivy. Also: slight refactor of doom/help-custom-variable.

core/autoload/help.el

@@ -392,9 +392,7 @@ variables, this only lists variables that exist to be customized (defined with
           (helpful--variable-at-point)
           (lambda (sym)
             (and (helpful--variable-p sym)
-                 (or (get sym 'custom-type)
-                     (get sym 'custom-package-version)
-                     (get sym 'custom-set))
+                 (custom-variable-p sym)
                  ;; Exclude minor mode state variables, which aren't meant to be
                  ;; modified directly, but through their associated function.
                  (not (or (and (string-suffix-p "-mode" (symbol-name sym))

modules/completion/ivy/config.el

@@ -235,6 +235,10 @@ results buffer.")
   (setq counsel-describe-function-function #'helpful-callable
         counsel-describe-variable-function #'helpful-variable)
 
+  ;; Decorate `doom/help-custom-variable' results the same way as
+  ;; `counsel-describe-variable' (adds value and docstring columns).
+  (ivy-configure 'doom/help-custom-variable :parent 'counsel-describe-variable)
+
   ;; Record in jumplist when opening files via counsel-{ag,rg,pt,git-grep}
   (add-hook 'counsel-grep-post-action-hook #'better-jumper-set-jump)
   (add-hook 'counsel-grep-post-action-hook #'recenter)