fix formatting

src/std/arc.md

@@ -3,25 +3,24 @@
 When shared ownership between threads is needed, `Arc`(Atomic Reference Counted) can be used. This struct, via the `Clone` implementation can create a reference pointer for the location of a value in the memory heap while increasing the reference counter. As it shares ownership between threads, when the last reference pointer to a value is out of scope, the variable is dropped.
 
 ```rust,editable
-
-fn main() {
 use std::sync::Arc;
 use std::thread;
 
-// This variable declaration is where its value is specified.
-let apple = Arc::new("the same apple");
+fn main() {
+    // This variable declaration is where its value is specified.
+    let apple = Arc::new("the same apple");
 
-for _ in 0..10 {
-    // Here there is no value specification as it is a pointer to a reference
-    // in the memory heap.
-    let apple = Arc::clone(&apple);
+    for _ in 0..10 {
+        // Here there is no value specification as it is a pointer to a reference
+        // in the memory heap.
+        let apple = Arc::clone(&apple);
 
-    thread::spawn(move || {
-        // As Arc was used, threads can be spawned using the value allocated
-        // in the Arc variable pointer's location.
-        println!("{:?}", apple);
-    });
-}
+        thread::spawn(move || {
+            // As Arc was used, threads can be spawned using the value allocated
+            // in the Arc variable pointer's location.
+            println!("{:?}", apple);
+        });
+    }
 }
 
 ```