doc: clarify ** usage

doc/040_backup.rst

@@ -402,8 +402,9 @@ This means, ``/bin`` matches ``/bin/bash`` but does not match ``/usr/bin/restic`
 Regular wildcards cannot be used to match over the directory separator ``/``,
 e.g. ``b*ash`` matches ``/bin/bash`` but does not match ``/bin/ash``. To match
 across an arbitrary number of subdirectories, use the special ``**`` wildcard.
-The ``**`` must be positioned between path separators. The pattern 
-``foo/**/bar`` matches:
+
+The ``**`` must be a **complete path component** (e.g. ``foo/**/bar``, not ``foo**`` or ``foo/**bar``).
+The pattern ``foo/**/bar`` matches:
 
 * ``/dir1/foo/dir2/bar/file``
 * ``/foo/bar/file``

doc/faq.rst

@@ -101,7 +101,7 @@ Restic handles globbing and expansion in the following ways:
 -  Environment variables are not expanded in the file read via ``--files-from``
 -  ``*`` is expanded for paths read via ``--files-from``
 -  e.g. For backup sources given to restic as arguments on the shell, neither glob expansion nor shell variable replacement is done. If restic is called as ``restic backup '*' '$HOME'``, it will try to backup the literal file(s)/dir(s) ``*`` and ``$HOME``
--  Double-asterisk ``**`` matches across zero or more subdirectories in exclude patterns (e.g. ``foo/**/bar``). This is a custom extension beyond Go's ``filepath.Match``; make sure the shell does not expand it (e.g. by quoting the pattern). See :ref:`backup-excluding-files` for details
+-  Double-asterisk ``**`` matches across zero or more subdirectories in exclude/include patterns (not ``--files-from``) when it is a complete path component (e.g. ``foo/**/bar``, not ``foo**`` or ``foo/**bar``). This is a custom extension beyond Go's ``filepath.Match``; make sure the shell does not expand it (e.g. by quoting the pattern). See :ref:`backup-excluding-files` for details
 
 
 How can I specify encryption passwords automatically?