[move.iterator] Avoid "defining" iterator_category

Use "determine" and "declare" instead.

Author: frederick-vs-ja

source/iterators.tex

@@ -4850,7 +4850,7 @@
 \end{codeblock}
 
 \pnum
-The member \grammarterm{typedef-name} \tcode{iterator_concept} is defined
+The member \grammarterm{typedef-name} \tcode{iterator_concept} is determined
 as follows:
 \begin{itemize}
 \item
@@ -4867,7 +4867,7 @@
 \end{itemize}
 
 \pnum
-The member \grammarterm{typedef-name} \tcode{iterator_category} is defined
+The member \grammarterm{typedef-name} \tcode{iterator_category} is declared
 if and only if the \grammarterm{qualified-id}
 \tcode{iterator_traits<It\-erator>::iterator_category}
 is valid and denotes a type.