fix: change number regex to not use lookbehind (#106)

Author: tmadeira

lib/index.js

@@ -39,7 +39,7 @@ const highlighters = [
   },
   {
     name: 'number',
-    regex: /((?<![a-zA-z])\d+(?:\.\d+)?)/g
+    regex: /(\b\d+(?:\.\d+)?)/g
   },
   {
     name: 'string',