P3287R2. Add note about std::simd alias

ChangeLog:

	* P3287_exploration_of_namespaces_for_simd/changelog.tex:
	* P3287_exploration_of_namespaces_for_simd/main.tex:
	* P3287_exploration_of_namespaces_for_simd/naming.tex:

P3287_exploration_of_namespaces_for_simd/changelog.tex

@@ -10,4 +10,5 @@ \section{Changelog}
 
 \begin{revision}
 \item Suggest and discuss \code{std::datapar::simd}, i.e. rename the namespace.
+\item Note that \code{std::simd} could be an alias to \code{std::datapar::simd}.
 \end{revision}

P3287_exploration_of_namespaces_for_simd/main.tex

@@ -1,6 +1,6 @@
 \newcommand\wgTitle{Exploration of namespaces for std::simd}
 \newcommand\wgName{Matthias Kretz <[email protected]>}
-\newcommand\wgDocumentNumber{D3287R2}
+\newcommand\wgDocumentNumber{P3287R2}
 \newcommand\wgGroup{LEWG}
 \newcommand\wgTarget{\CC{}26}
 \newcommand\wgAcknowledgements{Daniel Towner and Ruslan Arutyunyan contributed to this paper via discussions / reviews.}

P3287_exploration_of_namespaces_for_simd/naming.tex

@@ -35,6 +35,21 @@ \subsection{Namespace names}
 This package is about expressing data-parallelism, which only incidentally
 allows access to SIMD registers in a CPU.
 
+Note that if the namespace and type names differ, and the type name can stand
+on its own, it is possible to introduce an alias in the \code{std} namespace\footnote{
+  Thanks to Bryce for the suggestion!
+}:
+\smallskip\begin{lstlisting}
+namespace std {
+  namespace datapar {
+    template<class T, class Abi> class basic_simd;
+    template<class T, @\simdsizetype@ N> using simd = basic_simd<T, … >;
+  }
+  using datapar::basic_simd;
+  using datapar::simd;
+}
+\end{lstlisting}
+This is not proposed at this point.
 
 \subsection{Class template names}
 In any case, I suggest renaming \mask to \code{basic_mask}, and accordingly