Update documentation

doc/system/changes.adoc

@@ -14,6 +14,7 @@ https://www.boost.org/LICENSE_1_0.txt
 * Added a `boost::source_location` parameter to `throw_exception_from_error`.
 * `result<T>::value` now automatically supplies `BOOST_CURRENT_LOCATION` to
   `throw_exception_from_error` via a default argument.
+* Added an `errc::make_error_code` overload taking a source location.
 
 ## Changes in Boost 1.78
 

doc/system/reference.adoc

@@ -185,9 +185,13 @@ namespace errc {
 template<> struct is_error_condition_enum<errc::errc_t>
   { static const bool value = true; };
 
-constexpr error_code make_error_code( errc::errc_t e ) noexcept;
 constexpr error_condition make_error_condition( errc::errc_t e ) noexcept;
 
+constexpr error_code make_error_code( errc::errc_t e ) noexcept;
+
+error_code make_error_code( errc::errc_t e,
+  boost::source_location const * loc ) noexcept;
+
 } // namespace system
 } // namespace boost
 ```
@@ -256,6 +260,38 @@ void my_api_function( boost::system::error_code& ec )
 }
 ```
 
+```
+constexpr error_code make_error_code( errc::errc_t e,
+  boost::source_location const * loc ) noexcept;
+```
+[none]
+* {blank}
++
+Returns: :: `error_code( e, generic_category(), loc )`.
+
+Same as the above overload, but takes a source location.
+* {blank}
++
+```
+void my_api_function( boost::system::error_code& ec )
+{
+    void* p = std::malloc( 16 );
+
+    if( p == 0 )
+    {
+        // return ENOMEM
+
+        BOOST_STATIC_CONSTEXPR boost::source_location loc =
+          BOOST_CURRENT_LOCATION;
+
+        ec = make_error_code( boost::system::errc::out_of_memory, &loc );
+        return;
+    }
+
+    // use p
+}
+```
+
 ## <boost/system/{zwsp}error_category.hpp>
 
 ### error_category

include/boost/system/errc.hpp

@@ -37,7 +37,7 @@ BOOST_SYSTEM_CONSTEXPR inline error_code make_error_code( errc_t e ) BOOST_NOEXC
 }
 
 // explicit conversion:
-inline error_code make_error_code( errc_t e, boost::source_location const* loc ) BOOST_NOEXCEPT
+inline error_code make_error_code( errc_t e, boost::source_location const * loc ) BOOST_NOEXCEPT
 {
     return error_code( e, generic_category(), loc );
 }