Add entries for the doctest documentation.
diff --git a/Doc/lib/lib.tex b/Doc/lib/lib.tex
index e126cde..58e011f 100644
--- a/Doc/lib/lib.tex
+++ b/Doc/lib/lib.tex
@@ -109,6 +109,7 @@
 \input{libunicodedata}
 
 \input{libmisc}			% Miscellaneous Services
+\input{libdoctest}
 \input{libmath}
 \input{libcmath}
 \input{librandom}