Update docs for bool changes by Guido around April 6
diff --git a/Doc/lib/libimp.tex b/Doc/lib/libimp.tex
index 972128f..150f5b4 100644
--- a/Doc/lib/libimp.tex
+++ b/Doc/lib/libimp.tex
@@ -94,8 +94,8 @@
\end{funcdesc}
\begin{funcdesc}{lock_held}{}
-Return 1 if the import lock is currently held, else 0.
-On platforms without threads, always return 0.
+Return \code{True} if the import lock is currently held, else \code{False}.
+On platforms without threads, always return \code{False}.
On platforms with threads, a thread executing an import holds an internal
lock until the import is complete.
@@ -174,8 +174,8 @@
\end{funcdesc}
\begin{funcdesc}{is_frozen}{name}
-Return \code{1} if there is a frozen module (see
-\function{init_frozen()}) called \var{name}, or \code{0} if there is
+Return \code{True} if there is a frozen module (see
+\function{init_frozen()}) called \var{name}, or \code{False} if there is
no such module.
\end{funcdesc}