gatsby-plugin-catch-links: do not catch anchor links (href="#foobar") (…

…#2994)

Use anchor.hash instead of anchor.target.hash

https://www.w3schools.com/jsref/prop_anchor_hash.asp

Previously atleast IE 11 directed to page in / when there was <a> with href="#foobar" in non-root path, eg. /docs/

packages/gatsby-plugin-catch-links/src/catch-links.js

@@ -27,7 +27,7 @@ module.exports = function(root, cb) {
     // Don't catch links pointed to the same page but with a hash.
     if (
       anchor.pathname === window.location.pathname &&
-      anchor.target.hash !== ``
+      anchor.hash !== ``
     ) {
       return true
     }