* Links to notmuch messages

This package implements links to notmuch messages and "searches".
A search is a query to be performed by notmuch; it is the equivalent
to folders in other mail clients.  Similarly, mails are referred to
by a query, so both a link can refer to several mails.

Links have one the following forms
- ~notmuch:<search terms>~
- ~notmuch-search:<search terms>~

The first form open the queries in ~notmuch-show-mode~, whereas the
second link open it in ~notmuch-search-mode~.  Note that queries are
performed at the time the link is opened, and the result may be
different from when the link was stored.

#+html: <br><br>
#+html: <a href="https://github.com/tarsius/ol-notmuch/actions/workflows/compile.yml"><img alt="Compile" src="https://github.com/tarsius/ol-notmuch/actions/workflows/compile.yml/badge.svg"/></a>
#+html: <a href="https://stable.melpa.org/#/ol-notmuch"><img alt="MELPA Stable" src="https://stable.melpa.org/packages/ol-notmuch-badge.svg"/></a>
#+html: <a href="https://melpa.org/#/ol-notmuch"><img alt="MELPA" src="https://melpa.org/packages/ol-notmuch-badge.svg"/></a>
