Update <format> example and docs

Author: mborland

doc/modules/ROOT/pages/examples.adoc

@@ -231,22 +231,29 @@ This example can be found in the `examples/` folder as https://github.com/cppall
 
 [source, c++]
 ----
-#include <boost/decimal.hpp>
-#include <iostream>
-#include <format>
+include::example$format.cpp[]
+----
 
-int main()
-{
-    constexpr boost::decimal::decimal64_t val1 {314, -2};
-    constexpr boost::decimal::decimal32_t val2 {3141, -3};
+Expected Output:
+----
+Default Format:
+3.14
+3.141
 
-    std::cout << std::format("{:10.3e}", val1) << '\n';
-    std::cout << std::format("{:10.3e}", val2) << std::endl;
+Scientific Format:
+3.14e+00
+3.141e+00
 
-    return 0;
-}
+Scientific Format with Specified Precision:
+3.1e+00
+3.1e+00
+
+Scientific Format with Specified Precision and Padding:
+03.140e+00
+03.141e+00
 ----
 
+
 [#examples_print]
 == `<print>`
 

examples/format.cpp

@@ -1,10 +1,15 @@
 // Copyright 2025 Matt Borland
 // Distributed under the Boost Software License, Version 1.0.
 // https://www.boost.org/LICENSE_1_0.txt
+//
+// This example demonstrates usage and formatting of decimal types with <format>
 
-#include <boost/decimal.hpp>
+#include <boost/decimal/decimal32_t.hpp>    // For type decimal32_t
+#include <boost/decimal/decimal64_t.hpp>    // For type decimal64_t
+#include <boost/decimal/format.hpp>         // For <format> support (when available)
 #include <iostream>
 
+// This macro is defined in boost/decimal/format.hpp if the platform has <format> support
 #ifdef BOOST_DECIMAL_HAS_FORMAT_SUPPORT
 
 #include <format>