Update proposed/swift-interop.md

Co-authored-by: Rolf Bjarne Kvinge <rolf@xamarin.com>

Author: jkoritzinsky

proposed/swift-interop.md

@@ -99,7 +99,7 @@ Swift has a very strongly-defined lifetime and ownership model. This model is sp
 
 ##### Structs/Enums
 
-Like .NET, Swift as both value types and class types. The value types in Swift include both structs and enums. When passed at the ABI layer, they are generally treated as their composite structure and passed by value in registers. However, when Library Evolution mode is enabled, struct layouts are considered "opaque" and their size, alignment, and layout can vary between compile-time and runtime. As a result, all structs and enums in Library Evolution mode are passed by a pointer instead of in registers. Frozen structs and enums (annotated with the `@frozen` attribute) are not considered opaque and will be enregistered. We plan to interoperate with Swift through the Library Evolution mode, so we will generally be able to pass structures using opaque layout.
+Like .NET, Swift has both value types and class types. The value types in Swift include both structs and enums. When passed at the ABI layer, they are generally treated as their composite structure and passed by value in registers. However, when Library Evolution mode is enabled, struct layouts are considered "opaque" and their size, alignment, and layout can vary between compile-time and runtime. As a result, all structs and enums in Library Evolution mode are passed by a pointer instead of in registers. Frozen structs and enums (annotated with the `@frozen` attribute) are not considered opaque and will be enregistered. We plan to interoperate with Swift through the Library Evolution mode, so we will generally be able to pass structures using opaque layout.
 
 At the lowest level of the calling convention, we do not consider Library Evolution to be a different calling convention than the Swift calling convention. Library Evolution requires that some types are passed by a pointer/reference, but it does not fundamentally change the calling convention.