[tuple.cnstr] Do not use code font for cardinal number 1 (#6785)

Author: jwakely

source/utilities.tex

@@ -2032,7 +2032,7 @@
 \tcode{true}, and
 
 \item
-either \tcode{sizeof...(Types)} is not \tcode{1}, or
+either \tcode{sizeof...(Types)} is not 1, or
 (when \tcode{Types...} expands to \tcode{T})
 \tcode{is_convertible_v<UTuple, T>} and
 \tcode{is_constructible_v<T, UTuple>} are both \tcode{false}.