gh-69686: Remove untrue part of __import__ replacement docs (#143261)

Remove untrue part of `__import__` replacement docs

The original statement effectively says that replacing `__import__` at global scope affects import statements, and not only that, but only import statements within the rest of the executing module. None of that has been true since at least Python 2.7, I think.

This was likely missed in #69686.

Author: Sachaa-Thanasius

Doc/reference/import.rst

@@ -832,9 +832,7 @@ entirely with a custom meta path hook.
 
 If it is acceptable to only alter the behaviour of import statements
 without affecting other APIs that access the import system, then replacing
-the builtin :func:`__import__` function may be sufficient. This technique
-may also be employed at the module level to only alter the behaviour of
-import statements within that module.
+the builtin :func:`__import__` function may be sufficient.
 
 To selectively prevent the import of some modules from a hook early on the
 meta path (rather than disabling the standard import system entirely),