[docs] Fix typo in catchret example

An example usage of catchret omitted the "to" in "to label" in
ExceptionHandling.rst.

llvm-svn: 247086
diff --git a/llvm/docs/ExceptionHandling.rst b/llvm/docs/ExceptionHandling.rst
index 9d82845..5b495d9 100644
--- a/llvm/docs/ExceptionHandling.rst
+++ b/llvm/docs/ExceptionHandling.rst
@@ -715,7 +715,7 @@
 
   invoke.cont.3:                                    ; preds = %catch.body
     %9 = load i32, i32* %e, align 4
-    catchret %catch label %return
+    catchret %catch to label %return
 
   catchend:                                         ; preds = %lpad.catch, %catch.body
     catchendpad unwind label %lpad.terminate