fix: Set face attrs for error-warning-info messages

This was originally written in doomemacs#7814. But the commit c8b5bf7 didn't
include them when adapting changes from the original PR. Without this
settings, the messages from error-warning-info are all of same color.

modules/checkers/syntax/config.el

@@ -71,6 +71,9 @@
   :unless (modulep! +flymake)
   :hook (flycheck-mode . +syntax-init-popups-h)
   :config
+  (set-face-attribute 'flycheck-posframe-info-face nil :inherit 'font-lock-variable-name-face)
+  (set-face-attribute 'flycheck-posframe-warning-face nil :inherit 'warning)
+  (set-face-attribute 'flycheck-posframe-error-face nil :inherit 'error)
   (if (modulep! +icons)
       (setq flycheck-posframe-warning-prefix "⚠ "
             flycheck-posframe-info-prefix "ⓘ "