Add a load-bearing escape into the comment regex

Some other tooling may not understand javascript specific semantics for
regexes and really mess with someone's day!

![simpsons load bearing poster](https://media.giphy.com/media/l2JdUolkmRLmZM9Fu/giphy.gif)

src/lib/css-parse.html

@@ -171,7 +171,8 @@
 
     // helper regexp's
     _rx: {
-      comments: /\/\*[^*]*\*+([^/*][^*]*\*+)*\//gim,
+      // warning, this regex contains load-bearing escapes
+      comments: /\/\*[^*]*\*+([^\/*][^*]*\*+)*\//gim,
       port: /@import[^;]*;/gim,
       customProp: /(?:^[^;\-\s}]+)?--[^;{}]*?:[^{};]*?(?:[;\n]|$)/gim,
       mixinProp:  /(?:^[^;\-\s}]+)?--[^;{}]*?:[^{};]*?{[^}]*?}(?:[;\n]|$)?/gim,