Added entry for libtabnanny.tex.

Doc/lib/lib.tex

@@ -90,6 +90,7 @@ and how to embed it in other applications.
 \input{libtoken}
 \input{libkeyword}
 \input{libtokenize}
+\input{libtabnanny}
 \input{libpyclbr}
 \input{libcode}
 \input{libcodeop}