Fix typo in binascii synopsis.

Doc/lib/libbinascii.tex

 \section{Built-in Module \module{binascii}}
 \declaremodule{builtin}{binascii}
 
-\modulesynopsis{Tools for converting between binary and various ascii-encoded binary
-representation}
+\modulesynopsis{Tools for converting between binary and various
+ascii-encoded binary representations.}
 
 
 The \module{binascii} module contains a number of methods to convert