Fix grammar, spotted by Hye-Shik Chang

Doc/lib/libunicodedata.tex

@@ -78,7 +78,7 @@ defines the following functions:
 \end{funcdesc}
 
 \begin{funcdesc}{mirrored}{unichr}
-  Returns the mirrored property of assigned to the Unicode character
+  Returns the mirrored property assigned to the Unicode character
   \var{unichr} as integer. Returns \code{1} if the character has been
   identified as a ``mirrored'' character in bidirectional text,
   \code{0} otherwise.