[dcl.struct.bind] Use conventional indexing markup

Author: JohelEGP

source/declarations.tex

@@ -6629,7 +6629,7 @@
 \pnum
 If \tcode{E} is an array type with element type \tcode{T}, the number
 of elements in the \grammarterm{identifier-list} shall be equal to the
-number of elements of \tcode{E}. Each \tcode{v}$_i$ is the name of an
+number of elements of \tcode{E}. Each $\tcode{v}_i$ is the name of an
 lvalue that refers to the element $i$ of the array and whose type
 is \tcode{T}; the referenced type is \tcode{T}.
 \begin{note}
@@ -6698,7 +6698,7 @@
 Designating the non-static data members of \tcode{E} as
 $\tcode{m}_0$, $\tcode{m}_1$, $\tcode{m}_2, \dotsc$
 (in declaration order),
-each \tcode{v}$_i$ is the
+each $\tcode{v}_i$ is the
 name of an lvalue that refers to the member \tcode{m}$_i$ of \exposid{e} and
 whose type is
 that of \tcode{\exposidnc{e}.$\tcode{m}_i$}\iref{expr.ref};