Update Exercises Directory Names to Reflect Order

exercises/00_intro/README.md

@@ -0,0 +1,8 @@
+# Intro
+
+Rust uses the `print!` and `println!` macros to print text to the console.
+
+## Further information
+
+- [Hello World](https://doc.rust-lang.org/rust-by-example/hello.html)
+- [Formatted print](https://doc.rust-lang.org/rust-by-example/hello/print.html)