docs ~ add customized assertion example

examples/pretty_assertion_custom.rs

@@ -0,0 +1,14 @@
+#[allow(unused_imports)]
+use pretty_assertions;
+
+// note in docs/PR that "I don't think it's possible" to design a helper macro that simplifies the `assert_eq` generation
+// ... a generator macro "shadows" the std? `assert_eq!` macro at a lower scope level (terminology?) causing an error
+
+macro_rules! assert_eq { ($($arg:tt)+) => ({
+    pretty_assertions::with_config_assert_eq!(
+        pretty_assertions::AssertConfig { style: pretty_assertions::Color::Yellow.normal(), auto_label: true, prefix_left: "<<=", prefix_right: "=>>", prefix: "<=>", ..Default::default() },
+        $($arg)+
+    )
+})}
+
+include!("standard_assertion.rs");