This new context menu entry will be available only when the
advanced setting `filterAuthorMode` is set to `true`. See:
https://github.com/gorhill/uBlock/wiki/Advanced-settings#filterauthormode
The purpose is for filter list maintainers to easily access
the source code of web pages when investigating filter issues,
without having to necessarily go through the logger.
Additionally an input field to enter URL directly has been
added to the code viewer for convenience.
This commits add the ability to open html/css/script
resources from the logger, as a formatted and syntax-
highligthed document.
The goal is to make it easier for filter list authors to
investigate filter-related issues.
