Document that filter is added in 2.2.
diff --git a/Doc/lib/libfnmatch.tex b/Doc/lib/libfnmatch.tex
index 888580a6..8ef0fee 100644
--- a/Doc/lib/libfnmatch.tex
+++ b/Doc/lib/libfnmatch.tex
@@ -47,6 +47,7 @@
 Return the subset of the list of \var{names} that match \var{pattern}.
 It is the same as \code{[n for n in names if fnmatch(n, pattern)]}, but
 implemented more efficiently.
+\versionadded{2.2}
 \end{funcdesc}
 
 \begin{seealso}