[variant.assign] Introduce bullets for 'If an exception is thrown...' phrases. (#1069)

Fixes #822.

Author: jensmaurer

source/utilities.tex

@@ -4019,13 +4019,15 @@
 This function shall not participate in overload resolution unless
 \tcode{is_copy_constructible_v<$T_i$> \&\& is_move_constructible_v<$T_i$> \&\& is_copy_assignable_v<$T_i$>}
 is \tcode{true} for all $i$.
-If an exception is thrown during the call to $T_j$'s copy assignment,
+\begin{itemize}
+\item If an exception is thrown during the call to $T_j$'s copy assignment,
 the state of the contained value is as defined by the exception safety
 guarantee of $T_j$'s copy assignment; \tcode{index()} will be $j$.
-If an exception is thrown during the call to $T_j$'s copy construction
+\item If an exception is thrown during the call to $T_j$'s copy construction
 (with $j$ being \tcode{rhs.index()}), \tcode{*this} will remain unchanged.
-If an exception is thrown during the call to $T_j$'s move construction,
+\item If an exception is thrown during the call to $T_j$'s move construction,
 the \tcode{variant} will hold no value.
+\end{itemize}
 \end{itemdescr}
 
 \indexlibrarymember{operator=}{variant}%
@@ -4062,11 +4064,13 @@
 \tcode{true} for all $i$.
 The expression inside \tcode{noexcept} is equivalent to:
 \tcode{is_nothrow_move_constructible_v<$T_i$> \&\& is_nothrow_move_assignable_v<$T_i$>} for all $i$.
-If an exception is thrown during the call to $T_j$'s move construction
+\begin{itemize}
+\item If an exception is thrown during the call to $T_j$'s move construction
 (with $j$ being \tcode{rhs.index())}, the \tcode{variant} will hold no value.
-If an exception is thrown during the call to $T_j$'s move assignment,
+\item If an exception is thrown during the call to $T_j$'s move assignment,
 the state of the contained value is as defined by the exception safety
 guarantee of $T_j$'s move assignment; \tcode{index()} will be $j$.
+\end{itemize}
 \end{itemdescr}
 
 \indexlibrarymember{operator=}{variant}%
@@ -4121,12 +4125,14 @@
 \pnum
 The expression inside \tcode{noexcept} is equivalent to:
 \tcode{is_nothrow_assignable_v<$T_j$\&, T> \&\& is_nothrow_constructible_v<$T_j$, T>}.
-If an exception is thrown during the assignment of \tcode{std::forward<T>(t)}
+\begin{itemize}
+\item If an exception is thrown during the assignment of \tcode{std::forward<T>(t)}
 to the value contained in \tcode{*this}, the state of the contained value and
 \tcode{t} are as defined by the exception safety guarantee of the assignment
 expression; \tcode{valueless_by_exception()} will be \tcode{false}.
-If an exception is thrown during the initialization of the contained value,
+\item If an exception is thrown during the initialization of the contained value,
 the \tcode{variant} object might not hold a value.
+\end{itemize}
 \end{itemdescr}
 
 \rSec3[variant.mod]{Modifiers}