Fix some markup errors that prevented formatting, and one that didn't.

Doc/tut/tut.tex

@@ -1755,9 +1755,10 @@ item, then to the result and the next item, and so on.  For example,
 
 \subsection{List Comprehensions}
 
-List comprehensions provide a concise way to create lists without resorting
-to use of the \func{map()} or \func{filter()} functions.  The resulting
-construct tends often to be clearer than use of those functions.
+List comprehensions provide a concise way to create lists without
+resorting to use of the \function{map()} or \function{filter()}
+functions.  The resulting construct tends often to be clearer than use
+of those functions.
 
 \begin{verbatim}
 >>> spcs = ["  Apple", " Banana ", "Coco  nut  "]
@@ -1777,7 +1778,7 @@ construct tends often to be clearer than use of those functions.
 \section{The \keyword{del} statement \label{del}}
 
 There is a way to remove an item from a list given its index instead
-of its value: the \code{del} statement.  This can also be used to
+of its value: the \keyword{del} statement.  This can also be used to
 remove slices from a list (which we did earlier by assignment of an
 empty list to the slice).  For example: