replace ASCII by macro call
diff --git a/Doc/tut.tex b/Doc/tut.tex
index 2e11352..933c51e 100644
--- a/Doc/tut.tex
+++ b/Doc/tut.tex
@@ -1398,7 +1398,7 @@
items of two sequences compare equal, the sequences are considered
equal. If one sequence is an initial subsequence of the other, the
shorted sequence is the smaller one. Lexicographical ordering for
-strings uses the ASCII ordering for individual characters. Some
+strings uses the \ASCII{} ordering for individual characters. Some
examples of comparisons between sequences with the same types:
\bcode\begin{verbatim}
@@ -3301,7 +3301,7 @@
used equally well for moving objects around on a network or store them
in a database. For ease of debugging, and the inevitable occasional
manual patch-up, the constructed byte streams consist of printable
-ASCII characters only (though it's not designed to be pretty).
+\ASCII{} characters only (though it's not designed to be pretty).
The module \code{shelve} provides a simple model for storing objects
on files. The operation \code{shelve.open(filename)} returns a