gh-148588: Drop redundant __contains__ clarification from simple_stmts and whatsnew

Author: johnslavik

Doc/reference/simple_stmts.rst

@@ -931,8 +931,7 @@ Compatibility mode via ``__lazy_modules__``
 As an alternative to using the :keyword:`lazy` keyword, a module can opt
 into lazy loading for specific imports by defining a module-level
 :attr:`~module.__lazy_modules__` variable.  When present, it must be a
-container (an object implementing :meth:`~object.__contains__`) of fully
-qualified module name strings.  Any regular (non-``lazy``)
+container of fully qualified module name strings.  Any regular (non-``lazy``)
 :keyword:`import` statement at module scope whose target appears in
 :attr:`!__lazy_modules__` is treated as a lazy import, exactly as if the
 :keyword:`lazy` keyword had been used.

Doc/whatsnew/3.15.rst

@@ -185,8 +185,8 @@ raise :exc:`SyntaxError`).
 For code that cannot use the ``lazy`` keyword directly (for example, when
 supporting Python versions older than 3.15 while still leveraging lazy
 imports on 3.15+), a module can define
-:attr:`~module.__lazy_modules__` as a container (an object implementing
-:meth:`~object.__contains__`) of fully qualified module name strings.  Regular ``import`` statements for those modules are then treated
+:attr:`~module.__lazy_modules__` as a container of fully qualified module
+name strings.  Regular ``import`` statements for those modules are then treated
 as lazy, with the same semantics as the ``lazy`` keyword::
 
    __lazy_modules__ = ["json", "pathlib"]