Update url to markedjs (#601)

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* [x] Make sure you are merging your commits to `master` branch.
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Related: #410

This updates urls to marked github repo and documentation.

src/core/render/compiler.js

@@ -163,7 +163,7 @@ export class Compiler {
 
     /**
      * Render anchor tag
-     * @link https://github.com/chjj/marked#overriding-renderer-methods
+     * @link https://github.com/markedjs/marked#overriding-renderer-methods
      */
     origin.heading = renderer.heading = function (text, level) {
       const nextToc = {level, title: text}