doc: gccgo now supports method expressions and multiple init functions.

R=gri
CC=golang-dev
https://golang.org/cl/4314047

doc/go_spec.html

 <!-- title The Go Programming Language Specification -->
-<!-- subtitle Version of March 15, 2011 -->
+<!-- subtitle Version of March 28, 2011 -->
 
 <!--
 TODO
@@ -5147,6 +5147,4 @@ The following minimal alignment properties are guaranteed:
 <h2 id="Implementation_differences"><span class="alert">Implementation differences - TODO</span></h2>
 <ul>
 	<li><span class="alert">Implementation does not honor the restriction on goto statements and targets (no intervening declarations).</span></li>
-	<li><span class="alert">Gccgo: Method expressions are partially implemented.</span></li>
-	<li><span class="alert">Gccgo: allows only one init() function per source file.</span></li>
 </ul>