refactor: add #[non_exhaustive] attributes to enums (#304)

.changes/non_exhaustive.md

@@ -0,0 +1,5 @@
+---
+"wry": minor
+---
+
+Mark enums as `#[non_exhaustive]` to prevent breaking changes on enum update.

src/lib.rs

@@ -105,6 +105,7 @@ pub mod webview;
 pub type Result<T> = std::result::Result<T, Error>;
 
 /// Errors returned by wry.
+#[non_exhaustive]
 #[derive(Error, Debug)]
 pub enum Error {
   #[cfg(target_os = "linux")]

src/webview/mod.rs

@@ -453,6 +453,7 @@ impl RpcResponse {
 }
 
 /// An event enumeration sent to [`FileDropHandler`].
+#[non_exhaustive]
 #[derive(Debug, Serialize, Clone)]
 pub enum FileDropEvent {
   /// The file(s) have been dragged onto the window, but have not been dropped yet.