[tuple.elem] Canonicalize comments in example. (#3161)

Author: jensmaurer

source/utilities.tex

@@ -1901,9 +1901,9 @@
 \begin{example}
 \begin{codeblock}
   const tuple<int, const int, double, double> t(1, 2, 3.4, 5.6);
-  const int& i1 = get<int>(t);        // OK. Not ambiguous. \tcode{i1 == 1}
-  const int& i2 = get<const int>(t);  // OK. Not ambiguous. \tcode{i2 == 2}
-  const double& d = get<double>(t);   // ERROR. ill-formed
+  const int& i1 = get<int>(t);                  // OK, \tcode{i1} has value \tcode{1}
+  const int& i2 = get<const int>(t);            // OK, \tcode{i2} has value \tcode{2}
+  const double& d = get<double>(t);             // error: type \tcode{double} is not unique within \tcode{t}
 \end{codeblock}
 \end{example}
 \end{itemdescr}