[tuple.special] Use maths operators

Author: tkoeppe

source/utilities.tex

@@ -2498,8 +2498,8 @@
 \begin{itemdescr}
 \pnum
 \remarks This function shall not participate in overload resolution
-unless \tcode{is_swappable_v<$T_i$>} is \tcode{true}
-for all $i$, where $0 <= i$ and $i <$ \tcode{sizeof...(Types)}.
+unless \tcode{is_swappable_v<T$_i$>} is \tcode{true}
+for all $i$, where $0 \leq i < \text{\tcode{sizeof...(Types)}}$.
 The expression inside \tcode{noexcept} is equivalent to:
 
 \begin{codeblock}