DOC: Use two underscores for links with embedded URLs

Closes #13613.

Author: timhoffm

doc/usage/restructuredtext/basics.rst

@@ -208,11 +208,19 @@ Hyperlinks
 External links
 ~~~~~~~~~~~~~~
 
-Use ```Link text <https://domain.invalid/>`_`` for inline web links.  If the
+Use ```Link text <https://domain.invalid/>`__`` for web links.  If the
 link text should be the web address, you don't need special markup at all, the
 parser finds links and mail addresses in ordinary text.
 
-.. important:: There must be a space between the link text and the opening \< for the URL.
+.. important::
+
+   There must be a space between the link text and the opening \< for the URL.
+
+   Use two trailing underscores when embedding the URL. - Technically, a single
+   underscore works as well, but that would create a named reference instead of
+   an anonymous one. Named references typically do not have a benefit when the
+   URL is embedded. However, they have the disadvantage that you must make sure
+   that you do not use "Link text" in another link in your document.
 
 You can also separate the link and the target definition (:duref:`ref
 <hyperlink-targets>`), like this::