Fix trailing whitespace.

Author: zygoloid

source/iostreams.tex

@@ -6695,7 +6695,7 @@
 If \tcode{os.rdbuf()} is a
 \tcode{basic_osyncbuf<charT, traits, Allocator>*} \tcode{buf},
 calls \tcode{buf->set_emit_on_sync(true)}.
-Otherwise this manipulator has no effect. 
+Otherwise this manipulator has no effect.
 \begin{note}
 To work around the issue that the
 \tcode{Allocator} template argument can not be deduced,
@@ -6720,7 +6720,7 @@
 If \tcode{os.rdbuf()} is a
 \tcode{basic_osyncbuf<charT, traits, Allocator>*} \tcode{buf},
 calls \tcode{buf->set_emit_on_sync(false)}.
-Otherwise this manipulator has no effect. 
+Otherwise this manipulator has no effect.
 
 \pnum
 \returns
@@ -6738,9 +6738,9 @@
 \effects
 \tcode{os.flush()}.
 Then, if \tcode{os.rdbuf()} is a
-\tcode{basic_osyncbuf<charT, traits, Allocator>*} \tcode{buf}, 
-calls \tcode{buf->emit()}. 
- 
+\tcode{basic_osyncbuf<charT, traits, Allocator>*} \tcode{buf},
+calls \tcode{buf->emit()}.
+
 \pnum
 \returns
 \tcode{os}.