Fix underscore typo in <special_name>

Author: orivej

abi.html

@@ -4588,7 +4588,7 @@ <h5><a href="#mangling-transaction-safe"> 5.1.4.5 Transaction-Safe Function
 point used for calls during a transaction.  The mangled name of the transaction entry point is the normal mangling prefixed with GTt.
 
 <pre><font color=blue><code>
-  &lt;special_name> ::= GTt &lt;encoding>
+  &lt;special-name&gt; ::= GTt &lt;encoding&gt;
 </pre></font></code>
 
 <a name="mangling-type">