Add basic working example of multicount.

inquire/examples/multicount.rs

@@ -0,0 +1,30 @@
+use inquire::{
+    formatter::MultiCountFormatter, list_option::ListOption, validator::Validation, MultiCount,
+};
+
+fn main() {
+    let options = vec![
+        "Banana",
+        "Apple",
+        "Strawberry",
+        "Grapes",
+        "Lemon",
+        "Tangerine",
+        "Watermelon",
+        "Orange",
+        "Pear",
+        "Avocado",
+        "Pineapple",
+    ];
+
+    let formatter: MultiCountFormatter<'_, &str> = &|a| format!("{} different fruits", a.len());
+
+    let ans = MultiCount::new("Select the fruits for your shopping list:", options)
+        .with_formatter(formatter)
+        .prompt();
+
+    match ans {
+        Ok(_) => println!("I'll get right on it"),
+        Err(_) => println!("The shopping list could not be processed"),
+    }
+}