Fix password example too

src/prompts/password.rs

@@ -159,7 +159,7 @@ impl<'a> Password<'a> {
     ///     let password: String = Password::new()
     ///         .with_prompt("Enter password")
     ///         .validate_with(|input: &String| -> Result<(), &str> {
-    ///             if input.len() > 8 {
+    ///             if input.chars().count() > 8 {
     ///                 Ok(())
     ///             } else {
     ///                 Err("Password must be longer than 8")