[doc] Remove superfluous comment about equal in f-strings (GH-22006)



Automerge-Triggered-By: @kushaldas
diff --git a/Doc/reference/lexical_analysis.rst b/Doc/reference/lexical_analysis.rst
index 4c0f568..19ba83a 100644
--- a/Doc/reference/lexical_analysis.rst
+++ b/Doc/reference/lexical_analysis.rst
@@ -702,7 +702,7 @@
 declared.
 
 .. versionadded:: 3.8
-   The equal sign ``'='`` was added in Python 3.8.
+   The equal sign ``'='``.
 
 If a conversion is specified, the result of evaluating the expression
 is converted before formatting.  Conversion ``'!s'`` calls :func:`str` on