Doc: Simplify platform.machine() documentation and clarify output differences

Author: Aniketsy

Doc/library/platform.rst

@@ -56,13 +56,7 @@ Cross platform
    Returns the machine type, e.g. ``'AMD64'``. An empty string is returned if the
    value cannot be determined.
 
-   .. note::
-
-      The output of :func:`platform.machine` is system-dependent and may differ
-      in casing and naming conventions across platforms. For example, on Apple
-      Silicon macOS it may return ``'arm64'`` (lowercase), while on Windows-on-ARM
-      it may return ``'ARM64'`` (uppercase). If you need consistent results,
-      normalize the output in your code.
+   The output is platform-dependent and may differ in casing and naming conventions.
 
 
 .. function:: node()