Use \code{True} (or False) instead of true/false.

Not sure if code is correct, but that is what's in this file.
I've seen \constant{True} in other places.

Doc/lib/libstdtypes.tex

@@ -547,8 +547,8 @@ error handling scheme.  The default for \var{errors} is
 \end{methoddesc}
 
 \begin{methoddesc}[string]{endswith}{suffix\optional{, start\optional{, end}}}
-Return true if the string ends with the specified \var{suffix},
-otherwise return false.  With optional \var{start}, test beginning at
+Return \code{True} if the string ends with the specified \var{suffix},
+otherwise return \code{False}.  With optional \var{start}, test beginning at
 that position.  With optional \var{end}, stop comparing at that position.
 \end{methoddesc}
 
@@ -678,8 +678,8 @@ boundaries.  Line breaks are not included in the resulting list unless
 
 \begin{methoddesc}[string]{startswith}{prefix\optional{,
                                        start\optional{, end}}}
-Return true if string starts with the \var{prefix}, otherwise
-return false.  With optional \var{start}, test string beginning at
+Return \code{True} if string starts with the \var{prefix}, otherwise
+return \code{False}.  With optional \var{start}, test string beginning at
 that position.  With optional \var{end}, stop comparing string at that
 position.
 \end{methoddesc}