Fix some more subscripts for T, also fix cv in a few places. (#1805)

* Use \text{\cv}} in math mode, not \mathit.

* Replace Ti with $\tcode{T}_i$ for proper indexes.

Partially addresses #1139.

source/conversions.tex

@@ -289,10 +289,10 @@
 \begin{itemize}
 \item $\tcode{T}_1$ and $\tcode{T}_2$ are similar.
 
-\item For every $i > 0$, if \tcode{const} is in $\mathit{cv}_i^1$ then \tcode{const} is in $\mathit{cv}_i^2$, and similarly for \tcode{volatile}.
+\item For every $i > 0$, if \tcode{const} is in $\text{\cv}_i^1$ then \tcode{const} is in $\text{\cv}_i^2$, and similarly for \tcode{volatile}.
 
-\item If the $\mathit{cv}_i^1$ and $\mathit{cv}_i^2$ are different,
-then \tcode{const} is in every $\mathit{cv}_k^2$ for $0 < k < i$.
+\item If the $\text{\cv}_i^1$ and $\text{\cv}_i^2$ are different,
+then \tcode{const} is in every $\text{\cv}_k^2$ for $0 < k < i$.
 \end{itemize}
 
 \begin{note}

source/templates.tex

@@ -7762,15 +7762,15 @@
 \tcode{A}
 is a type
 \begin{indented}
-$\mathit{cv}_{1,0}$ ``pointer to $\ldots$'' $\mathit{cv}_{1,n-1}$ ``pointer to''
-$\mathit{cv}_{1,n}$ \tcode{T1}
+$\text{\cv}_{1,0}$ ``pointer to $\ldots$'' $\text{\cv}_{1,n-1}$ ``pointer to''
+$\text{\cv}_{1,n}$ \tcode{T1}
 \end{indented}
 and
 \tcode{P}
 is a type
 \begin{indented}
-$\mathit{cv}_{2,0}$ ``pointer to $\ldots$'' $\mathit{cv}_{2,n-1}$ ``pointer to''
-$\mathit{cv}_{2,n}$ \tcode{T2},
+$\text{\cv}_{2,0}$ ``pointer to $\ldots$'' $\text{\cv}_{2,n-1}$ ``pointer to''
+$\text{\cv}_{2,n}$ \tcode{T2},
 \end{indented}
 then the cv-unqualified
 \tcode{T1}

source/threads.tex

@@ -518,7 +518,7 @@
 
 \begin{itemdescr}
 \pnum
-\requires\ \tcode{F} and each \tcode{Ti} in \tcode{Args} shall satisfy the
+\requires\ \tcode{F} and each $\tcode{T}_i$ in \tcode{Args} shall satisfy the
 \tcode{MoveConstructible} requirements.
 \tcode{%
 \placeholdernc{INVOKE}(\brk{}%
@@ -4785,7 +4785,7 @@
 
 \begin{itemdescr}
 \pnum
-\requires \tcode{F} and each \tcode{Ti} in \tcode{Args} shall
+\requires \tcode{F} and each $\tcode{T}_i$ in \tcode{Args} shall
 satisfy the
 \tcode{MoveConstructible} requirements, and
 \begin{codeblock}