Fixup indentation

src/array_string.rs

@@ -45,7 +45,7 @@ impl<A: Array<Item=u8>> ArrayString<A> {
         }
     }
 
-    /// Create a new `ArrayString` from a string slice.
+    /// Create a new `ArrayString` from a `str`.
     ///
     /// Capacity is inferred from the type parameter.
     ///