Fixing recipe to run nowadays

[roolo]

I wasn't able to use the recipe in current Calibre / on current macOS, so I did some fixes. I was fixing until I got following command to produce meaningful content, with no errors.

ebook-convert reading-list.recipe .epub --test -vv --debug-pipeline debug

Command is from https://manual.calibre-ebook.com/news.html#tips-for-developing-new-recipes

After changes in this PR I was able to generate news ebook in following

• Calibre 5.4.2
• macOS 10.15.7
• Python 3.8.6 (probably ;))

I made the changes in pyCharm, which has some PEP complains, which I agreed on to be fixed by pyCharm. This resulted in a bit more changes (mostly indentation). Pls diff the changes in some real diff tool. It is way less scary, than what Github shows.

[alex-ketch]

Thanks for the update @roolo. In case it helps anyone else stumbling across this, I had to grant Calibre Full Disk Access in System Preferences to get this working. This is so that it can read the Safari bookmarks/reading list file at ~/Library/Safari/Bookmarks.plist.