gh-76303: Improve -x option documentation

Expand the documentation for the -x command-line option to explain its
purpose and usage for turning Python scripts into Windows batch files,
with examples of batch file header lines.

Closes #76303.

Author: RoryGlenn

Doc/using/cmdline.rst

@@ -519,7 +519,21 @@ Miscellaneous options
 .. option:: -x
 
    Skip the first line of the source, allowing use of non-Unix forms of
-   ``#!cmd``.  This is intended for a DOS specific hack only.
+   ``#!cmd``.
+
+   This can be used to turn a Python script into a Windows batch file.
+   Similarly to adding a shebang line and setting the executable bit on Unix,
+   the extension of the Python script can be changed to ``.bat`` and the
+   following line can be added at the start of the script::
+
+      @py -x "%~f0" %* & exit /b
+
+   Or, to specify the path to the Python interpreter explicitly::
+
+      @"C:\Path\to\python.exe" -x "%~f0" %* & exit /b
+
+   Unlike a shebang line which is a Python comment, this line is not valid
+   Python syntax, and the :option:`-x` option is needed to skip it.
 
 
 .. option:: -X

Misc/NEWS.d/next/Documentation/2026-02-16-00-01-09.gh-issue-76303.h51xeQ.rst

@@ -0,0 +1,2 @@
+Improved documentation for the :option:`-x` command-line option, explaining
+its use for turning Python scripts into Windows batch files.