Improve diagnostics

Co-authored-by: Richard Wei <[email protected]>

Author: asl

include/swift/AST/DiagnosticsSIL.def

@@ -608,7 +608,7 @@ NOTE(autodiff_cannot_differentiate_through_multiple_results,none,
 NOTE(autodiff_cannot_differentiate_through_inout_arguments,none,
      "cannot differentiate through 'inout' arguments", ())
 NOTE(autodiff_cannot_differentiate_through_direct_yield,none,
-     "cannot differentiate through a direct yield result", ())
+     "cannot differentiate through a '_read' accessor", ())
 NOTE(autodiff_enums_unsupported,none,
      "differentiating enum values is not yet supported", ())
 NOTE(autodiff_stored_property_parent_not_differentiable,none,