Fix typo: coverted --> converted. Reported by Francois Pinard.

Doc/ref/ref5.tex

@@ -813,7 +813,7 @@ obsolescent.
 The operators \code{<}, \code{>}, \code{==}, \code{>=}, \code{<=}, and
 \code{!=} compare
 the values of two objects.  The objects need not have the same type.
-If both are numbers, they are coverted to a common type.  Otherwise,
+If both are numbers, they are converted to a common type.  Otherwise,
 objects of different types \emph{always} compare unequal, and are
 ordered consistently but arbitrarily.