Update docs

Author: XuehaiPan

Doc/c-api/intro.rst

@@ -826,21 +826,17 @@ frequently used builds will be described in the remainder of this section.
 
 Compiling the interpreter with the :c:macro:`!Py_DEBUG` macro defined produces
 what is generally meant by :ref:`a debug build of Python <debug-build>`.
-:c:macro:`!Py_DEBUG` is enabled in the Unix build by adding
-:option:`--with-pydebug` to the :file:`./configure` command.
-It is also implied by the presence of the
-not-Python-specific :c:macro:`!_DEBUG` macro.  When :c:macro:`!Py_DEBUG` is enabled
-in the Unix build, compiler optimization is disabled.
 
-.. note::
-   On Windows, the :c:macro:`!Py_DEBUG` macro is not defined by default.
+On Unix, :c:macro:`!Py_DEBUG` can be enabled by adding :option:`--with-pydebug`
+to the :file:`./configure` command. This will also disable compiler optimization.
 
-   The :option:`--with-pydebug` option is not available on Windows. Instead, the
-   not-Python-specific :c:macro:`!_DEBUG` macro can be defined by the compiler
-   options and that will enable the :c:macro:`!Py_DEBUG` macro.
+On Windows, selecting a debug build (e.g., by passing the :option:`-d` option to
+:file:`PCbuild/build.bat`) automatically enables :c:macro:`!Py_DEBUG`.
+Additionally, the presence of the not-Python-specific :c:macro:`!_DEBUG` macro,
+when defined by the compiler, will also implicitly enable :c:macro:`!Py_DEBUG`.
 
 In addition to the reference count debugging described below, extra checks are
-performed, see :ref:`Python Debug Build <debug-build>`.
+performed. See :ref:`Python Debug Build <debug-build>` for more details.
 
 Defining :c:macro:`Py_TRACE_REFS` enables reference tracing
 (see the :option:`configure --with-trace-refs option <--with-trace-refs>`).