small typo corrected. updated brackets to braces
* updated brackets to braces
brackets are for example [], braces are {}
* Update concepts/functions/introduction.md
# Introduction
-Sometimes a certain piece of code needs to be used more than once. If that's the case, it might be convenient to put the code into a function. A function generally only performs one specific action. In Rust, the ```fn``` keyword is used to define functions. The code belonging to the function is always between brackets. The function named `main` is special because it is the entry point for programs. From that function you can call other functions.
+Sometimes a certain piece of code needs to be used more than once. If that's the case, it might be convenient to put the code into a function. A function generally only performs one specific action. In Rust, the ```fn``` keyword is used to define functions. The code belonging to the function is always between braces (i.e. `{}`). The function named `main` is special because it is the entry point for programs. From that function you can call other functions.
```rust
fn say_my_name(name: &str) -> &str {
