The parent is not URL-encoded when rendering a link for a new page that doesn't exist

For example, if the current document is named "C++ Examples", and contains a link to an inexistent document, then the URL will contain "&parent=C+++Examples", where + is parsed back into a space, so in the end, the actual parent is "C Examples".

This affects both rendering engines.

To fix, the parent must be encoded with URLEncoder.encode.