Longer macro parameter names

[SVN r13459]

doc/reference/comparison_less_equal.htm

@@ -30,6 +30,8 @@
  <p>Expands to <code>1</code> if <code>X &lt;= Y</code> and <code>0</code>
 otherwise.</p>
 
+<p><code>X</code> must expand to an integer literal.</p>
+
 <p>For example, <code><a href="comparison_less_equal.htm#BOOST_PP_LESS_EQUAL">BOOST_PP_LESS_EQUAL</a>(7,5)</code> expands to <code>0</code>.</p>
 
 <h3>Uses</h3>