AltCopy-0.4.0

Changes since AltCopy-0.3:
- Walk through enclosing elements looking up for an element with text attributes. It should help if a link is put inside a text element with a tooltip.
- Optional notifications of failures. Grant the relevant permission in the add-ons manager.
- A workaround for browser limitations when context menu opened from keyboard ([Menu] or [Shift+F10]) instead of mouse right click. It may be handy when cursor keys navigation (caret brows) is enabled ([F7]). Only text elements are currently supported.
- Firefox-112 and newer versions allows to work without the clipboard permission. Hopefully in Firefox-102 ESR the add-on should work a bit more reliable as well.
- This version does not request access to all sites on demand. You may grant this permission in the add-on manager to more reliable extraction of text from frames.
- Promptly fail if extraction script is delayed due to page loading. Stop page loading may help to get text attribute.

Extract datetime attribute value from <local-time>, <relative-time>, <time-ago>, and <time-until> elements that belong to a GitHub extension. It allows to obtain absolute date-time points for notes.