[stringstream.cons], [stringstream.members] Replace rSec2 with rSec3.

Author: jwakely

source/iostreams.tex

@@ -8262,7 +8262,7 @@
 \tcode{sb}, the \tcode{stringbuf} object.
 \end{itemize}
 
-\rSec2[stringstream.cons]{basic_stringstream constructors}
+\rSec3[stringstream.cons]{basic_stringstream constructors}
 
 \indexlibrary{\idxcode{basic_stringstream}!\idxcode{basic_stringstream}}%
 \begin{itemdecl}
@@ -8362,7 +8362,7 @@
 \effects \tcode{x.swap(y)}.
 \end{itemdescr}
 
-\rSec2[stringstream.members]{Member functions}
+\rSec3[stringstream.members]{Member functions}
 
 \indexlibrary{\idxcode{rdbuf}!\idxcode{basic_stringstream}}%
 \begin{itemdecl}