[range.join.iterator] Avoid "defining" typedef-names

Use "determine"/"declare" instead.

Author: frederick-vs-ja

source/ranges.tex

@@ -6653,7 +6653,7 @@
 \end{codeblock}
 
 \pnum
-\tcode{\exposid{iterator}::iterator_concept} is defined as follows:
+\tcode{\exposid{iterator}::iterator_concept} is determined as follows:
 \begin{itemize}
 \item If \exposid{ref-is-glvalue} is \tcode{true},
   \exposid{Base} models \libconcept{bidirectional_range}, and
@@ -6668,12 +6668,12 @@
 \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 \exposid{ref-is-glvalue} is \tcode{true},
 \exposid{Base} models \libconcept{forward_range}, and
 \tcode{range_reference_t<\exposid{Base}>} models \libconcept{forward_range}.
 In that case,
-\tcode{iterator::iter\-ator_category} is defined as follows:
+\tcode{iterator::iter\-ator_category} is determined as follows:
 \begin{itemize}
 \item Let \placeholder{OUTERC} denote
   \tcode{iterator_traits<iterator_t<\exposid{Base}>>::iterator_category}, and