refactor: use negated flags

Ref: 7a806521a92c

modules/lang/zig/config.el

@@ -20,8 +20,7 @@
   (when (modulep! +tree-sitter)
     (add-hook 'zig-mode-local-vars-hook #'tree-sitter! 'append))
 
-  (when (and (modulep! :checkers syntax)
-             (not (modulep! :checkers syntax +flymake)))
+  (when (modulep! :checkers syntax -flymake)
     (eval '(flycheck-define-checker zig
              "A zig syntax checker using zig's `ast-check` command."
              :command ("zig" "ast-check" (eval (buffer-file-name)))

modules/lang/zig/doctor.el

@@ -1,11 +1,11 @@
 ;; -*- lexical-binding: t; no-byte-compile: t; -*-
 ;;; lang/zig/doctor.el
 
-(assert! (or (not (modulep! +lsp))
+(assert! (or (modulep! -lsp)
              (modulep! :tools lsp))
          "This module requires (:tools lsp)")
 
-(assert! (or (not (modulep! +tree-sitter))
+(assert! (or (modulep! -tree-sitter)
              (modulep! :tools tree-sitter))
          "This module requires (:tools tree-sitter)")