Add attributes to syntax

presentation/chapters/en-US/syntax.chapter

@@ -99,8 +99,16 @@ Generally the `where` syntax is preferred.
 
 ---
 
+## Attributes
+
+Rust attributes are used for a number of different things. There is a full list of attributes in the [reference](https://doc.rust-lang.org/reference/attributes.html).
+
+<pre><code data-source="chapters/shared/code/syntax/15.rs" data-trim="hljs rust" class="lang-rust"></code></pre>
+
+---
+
 ## On Semicolons
 
 A line without a semi-colon implictly returns. Don't worry, the compiler will tell you if you forget it.
 
-<pre><code data-source="chapters/shared/code/syntax/15.rs" data-trim="hljs rust" class="lang-rust"></code></pre>
+<pre><code data-source="chapters/shared/code/syntax/16.rs" data-trim="hljs rust" class="lang-rust"></code></pre>

presentation/chapters/shared/code/syntax/15.rs

@@ -1,8 +1,7 @@
-fn do_thing() -> bool {
-    "Forgotten semicolon"
-    true
-}
+#[#[derive(Clone, Copy)]]
+struct Foo;
 
-fn main() {
-    do_thing()
-}
+#[inline(always)]
+fn bar() {}
+
+fn main() {}

presentation/chapters/shared/code/syntax/16.rs

@@ -0,0 +1,8 @@
+fn do_thing() -> bool {
+    "Forgotten semicolon"
+    true
+}
+
+fn main() {
+    do_thing()
+}