Implement [value; N] syntax support for array_vec! (#118)

* Implement `[value; N]` syntax for `array_vec!`

Also implement the `($array_type:ty)` form by just calling `default()` immediately, which makes more sense.

* Add tests for `[value; N]` macro form

* Implement `[value; N]` syntax for `tiny_vec!`

Also make the same improvement to the `($array_type:ty)` macro variant that I did for `array_vec!`.

* Add tests for `[value; N]` macro form

src/arrayvec.rs

@@ -36,11 +36,14 @@ macro_rules! array_vec {
     }
   };
   ($array_type:ty) => {
-    $crate::array_vec!($array_type =>)
+    $crate::ArrayVec::<$array_type>::default()
   };
   ($($elem:expr),*) => {
     $crate::array_vec!(_ => $($elem),*)
   };
+  ($elem:expr; $n:expr) => {
+    $crate::ArrayVec::from([$elem; $n])
+  };
   () => {
     $crate::array_vec!(_)
   };