[3.11] Doc/library/os.rst: os.waitid absent on MacOS (GH-104558) (#113554)

Doc/library/os.rst: `os.waitid` absent on MacOS (GH-104558)

* Doc/library/os.rst: `os.waitid` absent on MacOS

(cherry picked from commit db1c882)

Co-authored-by: John Hawkinson <[email protected]>
Co-authored-by: AN Long <[email protected]>

Author: 3 people

Doc/library/os.rst

@@ -4480,6 +4480,9 @@ written in Python, such as a mail server's external command delivery program.
 
    .. availability:: Unix, not Emscripten, not WASI.
 
+   .. note::
+      This function is not available on macOS.
+
    .. versionadded:: 3.3