feat(wpcarro/rust): Include std::fmt::Display example

Gotta know how to `to_string` things

Change-Id: I259ef61ecaf6ae7fabe0b3d211706ba5f429b3a7
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6057
Reviewed-by: wpcarro <wpcarro@gmail.com>
Autosubmit: wpcarro <wpcarro@gmail.com>
Tested-by: BuildkiteCI

users/wpcarro/scratch/rust/src/main.rs

@@ -0,0 +1,18 @@
+use serde::{Deserialize, Serialize};
+use serde_json::{json, Value};
+
+mod display;
+mod json;
+
+////////////////////////////////////////////////////////////////////////////////
+// Main
+////////////////////////////////////////////////////////////////////////////////
+
+fn main() {
+    let john: display::Person = display::Person {
+        fname: "John".to_string(),
+        lname: "Cleese".to_string(),
+        age: 82,
+    };
+    println!("Person: {}", john)
+}