perf(zig): quote flycheck-define-checker

Eager expansion of the flycheck-define-checker macro causes flycheck to
be unavoidably eager-loaded at startup, regardless of other deferral
techniques, slowing down startup considerably, as it pulls in a number
of associated packages/config with it.

modules/lang/zig/config.el

@@ -21,12 +21,13 @@
 
   (when (and (modulep! :checkers syntax)
              (not (modulep! :checkers syntax +flymake)))
-    (flycheck-define-checker zig
+    (eval '(flycheck-define-checker zig
              "A zig syntax checker using zig's `ast-check` command."
              :command ("zig" "ast-check" (eval (buffer-file-name)))
              :error-patterns
              ((error line-start (file-name) ":" line ":" column ": error: " (message) line-end))
              :modes zig-mode)
+          t)
     (add-to-list 'flycheck-checkers 'zig))
 
   (map! :localleader