isolated method treats self like parameter

Part of #145.

lang/spec.html

@@ -2039,14 +2039,20 @@ <h5>Methods</h5>
 method-name := identifier
 </pre>
 <p>
-The <code>method-name</code> of a <code>method-decl</code> must be distinct from
-the <code>method-name</code> of every other <code>method-decl</code> in the
+A <code>method-decl</code> describes a method of the object. The
+<code>method-name</code> of a <code>method-decl</code> must be distinct from the
+<code>method-name</code> of every other <code>method-decl</code> in the
 <code>object-type-descriptor</code> and from the <code>field-name</code> of
 every <code>object-field-descriptor</code> in the
 <code>object-type-descriptor</code>. Note that here is no method overloading.
 The <code>method-name</code> in a <code>method-decl</code> must not be
 <code>init</code>.
 </p>
+<p>
+The <code>isolated-qual</code> together with the <code>function-signature</code>
+give the function type of the method. An isolated method has the same access to
+the object on which the method is invoked that it has to parameters.
+</p>
 <pre
 class="grammar">remote-qual := <code>remote</code>
 </pre>