Add :lang json module

Removes json-mode from :lang data and adds LSP support (#2502).

modules/lang/json/config.el

@@ -0,0 +1,14 @@
+;;; lang/json/config.el -*- lexical-binding: t; -*-
+
+(use-package! json-mode
+  :mode "\\.js\\(?:on\\|[hl]int\\(?:rc\\)?\\)\\'"
+  :init
+  (when (featurep! +lsp)
+    (add-hook 'json-mode-local-vars-hook #'lsp!))
+  :config
+  (set-electric! 'json-mode :chars '(?\n ?: ?{ ?}))
+
+  (map! :after json-mode
+        :map json-mode-map
+        :localleader
+        "s" #'jsons-print-path))