[range.iota.iterator] Use "determine" for iterator_concept

Author: frederick-vs-ja

source/ranges.tex

@@ -3034,7 +3034,7 @@
 \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 \tcode{W} models \exposconcept{advanceable}, then
 \tcode{iterator_concept} is \tcode{random_access_iterator_tag}.