g.access: add note to manual: UNIX filesystem access controls and g.access actions are not supported by MS-Windows.

git-svn-id: https://svn.osgeo.org/grass/grass/branches/releasebranch_7_0@71160 15284696-431f-4ddb-bdfa-cd5b030d7da7

general/g.access/g.access.html

@@ -30,6 +30,9 @@ search path.  However, the data in a restricted mapset is still protected;
 any attempts to look for or use data in a restricted mapset will fail.  The
 user will simply not see any data listed for a restricted mapset.
 
+<p>UNIX filesystem access controls and <em>g.access</em> actions are not 
+supported by MS-Windows.
+
 <h2>SEE ALSO</h2>
 
 UNIX manual entries for <em>chmod</em> and <em>group</em>