[basic.lookup.argdep] Correct xref to point to the normative invisible

friend rule.

Author: zygoloid

source/basic.tex

@@ -1573,10 +1573,10 @@
 \item Any \grammarterm{using-directive}{s} in the associated namespace are
 ignored.
 
-\item Any namespace-scope friend functions or friend function templates
+\item Any namespace-scope friend functions or friend function templates\iref{class.friend}
 declared in associated classes are visible within their respective
 namespaces even if they are not visible during an ordinary
-lookup\iref{class.friend}.
+lookup\iref{namespace.memdef}.
 
 \item All names except those of (possibly overloaded) functions and
 function templates are ignored.