Update docs

Author: rolfmorel

mlir/include/mlir/Dialect/Transform/IR/TransformOps.td

@@ -423,6 +423,9 @@ def ApplyRegisteredPassOp : TransformDialectOp<"apply_registered_pass",
     : (!transform.any_param, !transform.any_param, !transform.any_op) -> !transform.any_op
     ```
 
+    Options' values which are `ArrayAttr`s are converted to comma-separated
+    lists of options. Likewise for params which associate multiple values.
+
     This op first looks for a pass pipeline with the specified name. If no such
     pipeline exists, it looks for a pass with the specified name. If no such
     pass exists either, this op fails definitely.