bpo-36798: Updating f-string docs for := use case (GH-13107)
diff --git a/Doc/reference/lexical_analysis.rst b/Doc/reference/lexical_analysis.rst
index fb04ccc..13adc1a 100644
--- a/Doc/reference/lexical_analysis.rst
+++ b/Doc/reference/lexical_analysis.rst
@@ -680,11 +680,12 @@
Expressions in formatted string literals are treated like regular
Python expressions surrounded by parentheses, with a few exceptions.
-An empty expression is not allowed, and a :keyword:`lambda` expression
-must be surrounded by explicit parentheses. Replacement expressions
-can contain line breaks (e.g. in triple-quoted strings), but they
-cannot contain comments. Each expression is evaluated in the context
-where the formatted string literal appears, in order from left to right.
+An empty expression is not allowed, and both :keyword:`lambda` and
+assignment expressions ``:=`` must be surrounded by explicit parentheses.
+Replacement expressions can contain line breaks (e.g. in triple-quoted
+strings), but they cannot contain comments. Each expression is evaluated
+in the context where the formatted string literal appears, in order from
+left to right.
If a conversion is specified, the result of evaluating the expression
is converted before formatting. Conversion ``'!s'`` calls :func:`str` on