Runtime::revisions does not need to be boxed

Runtime is contained within Zalsa which is Arc'd anyways.

src/runtime.rs

@@ -35,7 +35,7 @@ pub struct Runtime {
     /// revisions[i + 1]`, for all `i`. This is because when you
     /// modify a value with durability D, that implies that values
     /// with durability less than D may have changed too.
-    revisions: Box<[AtomicRevision; Durability::LEN]>,
+    revisions: [AtomicRevision; Durability::LEN],
 
     /// The dependency graph tracks which runtimes are blocked on one
     /// another, waiting for queries to terminate.
@@ -81,7 +81,7 @@ impl<V> StampedValue<V> {
 impl Default for Runtime {
     fn default() -> Self {
         Runtime {
-            revisions: Box::new([const { AtomicRevision::start() }; Durability::LEN]),
+            revisions: [const { AtomicRevision::start() }; Durability::LEN],
             revision_canceled: Default::default(),
             dependency_graph: Default::default(),
             table: Default::default(),