[basic.lookup.argdep] Add missing words

Author: lprv

source/basic.tex

@@ -2333,7 +2333,7 @@
 
 \pnum
 \begin{note}
-The associated namespace can include namespaces
+The set of associated namespaces can include namespaces
 already considered by ordinary unqualified lookup.
 \end{note}
 \begin{example}