[iterator.concept.winc] Format 'I' in code font (#4027)

Author: JohelEGP

source/iterators.tex

@@ -1417,7 +1417,7 @@
 \tcode{\exposid{is-integer-like}<I>} is \tcode{true}
 if and only if \tcode{I} is an integer-like type.
 \tcode{\exposid{is-signed-integer-like}<I>} is \tcode{true}
-if and only if I is a signed-integer-like type.
+if and only if \tcode{I} is a signed-integer-like type.
 
 \pnum
 Let \tcode{i} be an object of type \tcode{I}. When \tcode{i} is in the domain of