the swift.Slice type got removed a long time ago, being replaced with

what is now Swift.Array.  Update various internal stuff to refer to
Array instead of Slice.  NFC.


Swift SVN r14567

lib/Sema/CSApply.cpp

@@ -1885,7 +1885,7 @@ namespace {
       expr->setElementType(elementType);
 
       // Make sure that the result type is a slice type, even if
-      // canonicalization mapped it down to Slice<T>.
+      // canonicalization mapped it down to Array<T>.
       auto sliceType = dyn_cast<ArraySliceType>(resultType.getPointer());
       if (!sliceType) {
         resultType = tc.getArraySliceType(expr->getLoc(), elementType);