Fix typo reported in #964592. Will backport to 2.3.
diff --git a/Doc/ref/ref2.tex b/Doc/ref/ref2.tex
index c434468..7590592 100644
--- a/Doc/ref/ref2.tex
+++ b/Doc/ref/ref2.tex
@@ -348,7 +348,7 @@
\item[\code{__*}]
Class-private names. Names in this category, when used within the
- context of a class definition, are re-written to use a mangled for
+ context of a class definition, are re-written to use a mangled form
to help avoid name clashes between ``private'' attributes of base
and derived classes.
See section~\ref{atom-identifiers}, ``Identifiers (Names).''