[ostream.manip] Fix typo where "basic_osyncbuf" should be "basic_syncbuf" (#2004)

Author: timsong-cpp

source/iostreams.tex

@@ -6696,15 +6696,15 @@
 \pnum
 \effects
 If \tcode{os.rdbuf()} is a
-\tcode{basic_osyncbuf<charT, traits, Allocator>*},
+\tcode{basic_syncbuf<charT, traits, Allocator>*},
 called \tcode{buf} for the purpose of exposition,
 calls \tcode{buf->set_emit_on_sync(true)}.
 Otherwise this manipulator has no effect.
 \begin{note}
 To work around the issue that the
 \tcode{Allocator} template argument can not be deduced,
 implementations can introduce an intermediate base class
-to \tcode{basic_osyncbuf} that manages its \tcode{emit_on_sync} flag.
+to \tcode{basic_syncbuf} that manages its \tcode{emit_on_sync} flag.
 \end{note}
 
 \pnum
@@ -6722,7 +6722,7 @@
 \pnum
 \effects
 If \tcode{os.rdbuf()} is a
-\tcode{basic_osyncbuf<charT, traits, Allocator>*},
+\tcode{basic_syncbuf<charT, traits, Allocator>*},
 called \tcode{buf} for the purpose of exposition,
 calls \tcode{buf->set_emit_on_sync(false)}.
 Otherwise this manipulator has no effect.
@@ -6743,7 +6743,7 @@
 \effects
 Calls \tcode{os.flush()}.
 Then, if \tcode{os.rdbuf()} is a
-\tcode{basic_osyncbuf<charT, traits, Allocator>*},
+\tcode{basic_syncbuf<charT, traits, Allocator>*},
 called \tcode{buf} for the purpose of exposition,
 calls \tcode{buf->emit()}.