gh-110886 Doc: add a link to BNF Wikipedia article (#110887)

Co-authored-by: Hugo van Kemenade <hugovk@users.noreply.github.com>

diff --git a/Doc/reference/introduction.rst b/Doc/reference/introduction.rst
index 81f0a5c5d438839bf10347c9c8f368d8202c8154..cf186705e6e987b6a733c3dc90c6c32b2d10fab1 100644 (file)
--- a/Doc/reference/introduction.rst
+++ b/Doc/reference/introduction.rst
@@ -90,7 +90,8 @@ Notation
 
 .. index:: BNF, grammar, syntax, notation
 
-The descriptions of lexical analysis and syntax use a modified BNF grammar
+The descriptions of lexical analysis and syntax use a modified
+`Backus–Naur form (BNF) <https://en.wikipedia.org/wiki/Backus%E2%80%93Naur_form>`_ grammar
 notation.  This uses the following style of definition:
 
 .. productionlist:: notation