Markup fix.
 (backport from rev. 54951)
diff --git a/Doc/mac/using.tex b/Doc/mac/using.tex
index 5b5d9e8..ca522c6 100644
--- a/Doc/mac/using.tex
+++ b/Doc/mac/using.tex
@@ -151,7 +151,7 @@
 
 The standard tool for deploying standalone Python applications on the Mac is
 \program{py2app}. More information on installing and using py2app can be found
-at \url{http://undefined.org/python/#py2app}.
+at \url{http://undefined.org/python/\#py2app}.
 
 \section{Application Scripting}