[qty.expr.temp.general] Extend example with kilogram

docs/api_reference/src/quantities.tex

@@ -754,8 +754,10 @@
 The framework ensures the following assertion holds.
 \begin{codeblock}
 using namespace si::unit_symbols;
-static_assert(std::is_same_v<decltype(km / square(h)),
-                             derived_unit<si::kilo_<si::metre>, per<power<non_si::hour, 2>>>>);
+static_assert(
+  std::is_same_v<decltype(kg * km / square(h)),
+                 derived_unit<si::kilo_<struct si::gram>, si::kilo_<struct si::metre>,
+                              per<power<struct non_si::hour, 2>>>>);
 \end{codeblock}
 \end{example}