Blacklist Key_Menu for the purposes of shortcuts

This key could be set on Windows, but caused weirdness when attempting
to actually use it.
Newer manual installation instructions

Adjusts the information about Linux Anki files location (which is no
longer necessarily the home directory) and makes the navigation path in
the archive more explicit.
Web styling: parent icons in lists

Suppresses the up arrow symbol from links that appear by themselves
within lists in the article area. This stops the arrow from oddly
appearing to the left of "open configuration in main window" in the
"Available Window Shortcuts" list on /config/windows.