Added missing "{" for "\code <?stuff?>}".

Doc/lib/libxmllib.tex

@@ -143,7 +143,7 @@ string containing the text between the PI target and the closing delimiter,
 but not the delimiter itself.  For example, the instruction
 ``\code{<?XML text?>}'' will cause this method to be called with the
 arguments \code{'XML'} and \code{'text'}.  The default method does
-nothing.  Note that if a document starts with a \code <?xml ...?>}
+nothing.  Note that if a document starts with a \code{<?xml ...?>}
 tag, \code{handle_xml} is called to handle it.
 \end{funcdesc}
 

Doc/libxmllib.tex

@@ -143,7 +143,7 @@ string containing the text between the PI target and the closing delimiter,
 but not the delimiter itself.  For example, the instruction
 ``\code{<?XML text?>}'' will cause this method to be called with the
 arguments \code{'XML'} and \code{'text'}.  The default method does
-nothing.  Note that if a document starts with a \code <?xml ...?>}
+nothing.  Note that if a document starts with a \code{<?xml ...?>}
 tag, \code{handle_xml} is called to handle it.
 \end{funcdesc}