Remove extra period produced by previous change.

Doc/lib/libstdtypes.tex

@@ -393,9 +393,9 @@ item tuple must have a trailing comma, e.g., \code{(d,)}.
 
 Buffer objects are not directly supported by Python syntax, but can be
 created by calling the builtin function
-\function{buffer()}.\bifuncindex{buffer}.  They support
-concatenation and repetition, but the result is a new string object
-rather than a new buffer object.
+\function{buffer()}.\bifuncindex{buffer}  They support concatenation
+and repetition, but the result is a new string object rather than a
+new buffer object.
 \obindex{buffer}
 
 Xrange objects are similar to buffers in that there is no specific