v1.2.0

• cty: Applications can now implement a general subset of the cty operations when creating a capsule type. For more information, see Capsule Type Operation Definitions.
• cty: Values now support a new mechanism called Value Marks which can be used to transit additional metadata through expressions by marking the input values and then observing which marks propagated to the result value. This could be used, for example, to detect whether a value was derived from a particular other value in case that is useful for giving extra feedback in an error message.