session-name.xml: use the correct directive name and add the link to (GH-3642)

There is no directive `session.transid` in PHP. It's probably about the `session.use_trans_sid` directive instead `session.transid`, if I got the context right

Co-authored-by: Kamil Tekiela <[email protected]>
Co-authored-by: Christoph M. Becker <[email protected]>

Author: 3 people

reference/session/functions/session-name.xml

@@ -21,9 +21,9 @@
   <para>
    If a new session <parameter>name</parameter> is
    supplied, <function>session_name</function> modifies the HTTP cookie
-   (and output content when <literal>session.transid</literal> is
-   enabled). Once the HTTP cookie is
-   sent, <function>session_name</function> raises error.
+   (and outputs the content when <link linkend="ini.session.use-trans-sid">session.use_trans_sid</link> is
+   enabled). Once the HTTP cookie has been
+   sent, calling <function>session_name</function> raises an <constant>E_WARNING</constant>.
    <function>session_name</function> must be called
    before <function>session_start</function> for the session to work
    properly.