chore: update documentation

plugins/biometric/src/error.rs

@@ -4,12 +4,18 @@
 
 use serde::{ser::Serializer, Serialize};
 
+/// Alias for a [`Result`](std::result::Result) with the error type [`Error`].
 pub type Result<T> = std::result::Result<T, Error>;
 
+/// The error types returned by this plugin.
 #[derive(Debug, thiserror::Error)]
 pub enum Error {
+    /// An I/O error occurred.
     #[error(transparent)]
     Io(#[from] std::io::Error),
+    /// The invocation of the underlying Android or iOS plugin failed, for example because
+    /// biometric authentication was unavailable, was not enrolled, failed, or was canceled by
+    /// the user.
     #[cfg(mobile)]
     #[error(transparent)]
     PluginInvoke(#[from] tauri::plugin::mobile::PluginInvokeError),