bpo-31907: [doc] clarify that str.format() does not support arbitrary expressions (#25053)
diff --git a/Doc/library/string.rst b/Doc/library/string.rst
index 1bfd518..d935419 100644
--- a/Doc/library/string.rst
+++ b/Doc/library/string.rst
@@ -188,8 +188,8 @@
The :meth:`str.format` method and the :class:`Formatter` class share the same
syntax for format strings (although in the case of :class:`Formatter`,
subclasses can define their own format string syntax). The syntax is
-related to that of :ref:`formatted string literals <f-strings>`, but
-there are differences.
+related to that of :ref:`formatted string literals <f-strings>`, but it is
+less sophisticated and, in particular, does not support arbitrary expressions.
.. index::
single: {} (curly brackets); in string formatting