pythongh-110138: Improve grammar in idiomatic usage of __main__.py (

python#110142)

Doc/library/__main__.rst

@@ -238,9 +238,9 @@ package.  For more details, see :ref:`intra-package-references` in the
 Idiomatic Usage
 ^^^^^^^^^^^^^^^
 
-The contents of ``__main__.py`` typically isn't fenced with
-``if __name__ == '__main__'`` blocks.  Instead, those files are kept short,
-functions to execute from other modules.  Those other modules can then be
+The content of ``__main__.py`` typically isn't fenced with an
+``if __name__ == '__main__'`` block.  Instead, those files are kept
+short and import functions to execute from other modules.  Those other modules can then be
 easily unit-tested and are properly reusable.
 
 If used, an ``if __name__ == '__main__'`` block will still work as expected