backport bin() documentation
diff --git a/Doc/reference/lexical_analysis.rst b/Doc/reference/lexical_analysis.rst
index b548722..03e4c05 100644
--- a/Doc/reference/lexical_analysis.rst
+++ b/Doc/reference/lexical_analysis.rst
@@ -629,10 +629,11 @@
.. productionlist::
longinteger: `integer` ("l" | "L")
- integer: `decimalinteger` | `octinteger` | `hexinteger`
+ integer: `decimalinteger` | `octinteger` | `hexinteger` | `bininteger`
decimalinteger: `nonzerodigit` `digit`* | "0"
octinteger: "0" `octdigit`+
hexinteger: "0" ("x" | "X") `hexdigit`+
+ bininteger: "0" ("b" | "B") `bindigit`+
nonzerodigit: "1"..."9"
octdigit: "0"..."7"
hexdigit: `digit` | "a"..."f" | "A"..."F"