fix

book/node_modules/highlight.js/lib/languages/bnf.js

@@ -0,0 +1,39 @@
+/*
+Language: Backus–Naur Form
+Website: https://en.wikipedia.org/wiki/Backus–Naur_form
+Category: syntax
+Author: Oleg Efimov <efimovov@gmail.com>
+*/
+
+/** @type LanguageFn */
+function bnf(hljs) {
+  return {
+    name: 'Backus–Naur Form',
+    contains: [
+      // Attribute
+      {
+        className: 'attribute',
+        begin: /</,
+        end: />/
+      },
+      // Specific
+      {
+        begin: /::=/,
+        end: /$/,
+        contains: [
+          {
+            begin: /</,
+            end: />/
+          },
+          // Common
+          hljs.C_LINE_COMMENT_MODE,
+          hljs.C_BLOCK_COMMENT_MODE,
+          hljs.APOS_STRING_MODE,
+          hljs.QUOTE_STRING_MODE
+        ]
+      }
+    ]
+  };
+}
+
+module.exports = bnf;