docs: Some docs updated to reflect the latest formatting changes

docs/blog/posts/2.2.0-released.md

@@ -242,9 +242,9 @@ quantity q = (90. * km / h).in(mph);
 std::cout << "Number: " << q.numerical_value_in(mph) << "\n";
 std::cout << "Unit: " << q.unit << "\n";
 std::cout << "Dimension: " << q.dimension << "\n";
-std::println("{:{%N:.2f}%?%U}", q);
+std::println("{::N[.2f]}", q);
 std::println("{:.4f} in {} of {}", q.numerical_value_in(mph), q.unit, q.dimension);
-std::println("{:{%N:.4f} in %U of %D}", q);
+std::println("{:%N in %U of %D:N[.4f]}", q);
 ```
 
 ```text

docs/users_guide/framework_basics/the_affine_space.md

@@ -491,7 +491,7 @@ room_temp room_ref{};
 room_temp room_low = room_ref - number_of_steps * step_delta;
 room_temp room_high = room_ref + number_of_steps * step_delta;
 
-std::println("Room reference temperature: {} ({}, {:{%N:.2f}%?%U})\n",
+std::println("Room reference temperature: {} ({}, {::N[.2f]})\n",
              room_ref.quantity_from_zero(),
              room_ref.in(usc::degree_Fahrenheit).quantity_from_zero(),
              room_ref.in(si::kelvin).quantity_from_zero());

test/runtime/fmt_test.cpp

@@ -1006,7 +1006,7 @@ TEST_CASE("localization with the 'L' specifier", "[text][fmt][localization]")
   std::locale grp2{std::locale::classic(), new group2};
   std::locale grp3{std::locale::classic(), new group3};
 
-  SECTION("full format {:{%N:L}%?%U} on a quantity")
+  SECTION("full format on a quantity")
   {
     SECTION("default spec")
     {