Improve doc comments

No need to say "represents" when describing a type (all types represent
something in real world, they are not the real thing), and "ABI-compatible"
needs a dash.

PiperOrigin-RevId: 546813197

rust/cpp.rs

@@ -98,10 +98,10 @@ impl Drop for Arena {
     }
 }
 
-/// Represents serialized Protobuf wire format data. It's typically produced by
+/// Serialized Protobuf wire format data. It's typically produced by
 /// `<Message>.serialize()`.
 ///
-/// This struct is ABI compatible with the equivalent struct on the C++ side. It
+/// This struct is ABI-compatible with the equivalent struct on the C++ side. It
 /// owns (and drops) its data.
 #[repr(C)]
 pub struct SerializedData {

rust/upb.rs

@@ -130,7 +130,7 @@ impl Drop for Arena {
     }
 }
 
-/// Represents serialized Protobuf wire format data.
+/// Serialized Protobuf wire format data.
 ///
 /// It's typically produced by `<Message>::serialize()`.
 pub struct SerializedData {