Typo: thsi -> this. Closes SF bug #521450.

Doc/ref/ref7.tex

@@ -280,7 +280,7 @@ re-raised.  If the \keyword{finally} clause raises another exception or
 executes a \keyword{return} or \keyword{break} statement, the saved
 exception is lost.  A \keyword{continue} statement is illegal in the
 \keyword{finally} clause.  (The reason is a problem with the current
-implementation -- thsi restriction may be lifted in the future).  The
+implementation -- this restriction may be lifted in the future).  The
 exception information is not available to the program during execution of
 the \keyword{finally} clause.
 \kwindex{finally}