fix some markup errors

Doc/api/concrete.tex

@@ -170,14 +170,14 @@ There is no \cfunction{PyNone_Check()} function for the same reason.
 
 \begin{cfuncdesc}{unsigned long}{PyInt_AsUnsignedLongMask}{PyObject *io}
   Will first attempt to cast the object to a \ctype{PyIntObject} or
-  \ctypes{PyLongObject}, if it is not already one, and then return its
+  \ctype{PyLongObject}, if it is not already one, and then return its
   value as unsigned long.  This function does not check for overflow.
   \versionadded{2.3}
 \end{cfuncdesc}
 
 \begin{cfuncdesc}{unsigned long}{PyInt_AsUnsignedLongLongMask}{PyObject *io}
   Will first attempt to cast the object to a \ctype{PyIntObject} or
-  \ctypes{PyLongObject}, if it is not already one, and then return its
+  \ctype{PyLongObject}, if it is not already one, and then return its
   value as unsigned long long, without checking for overflow.
   \versionadded{2.3}
 \end{cfuncdesc}