fixup: i-th

Author: jensmaurer

source/templates.tex

@@ -1736,7 +1736,7 @@
 if $N = 0$ or if for each $i$ where $0 \le i < N$ in increasing order,
 $C$ is satisfied
 when replacing each pack expansion parameter
-with the corresponding $i$-th element.
+with the corresponding $i^\text{th}$ element.
 No substitution takes place for any $i$ greater than
 the smallest $i$ for which the constraint is not satisfied.