use [] and [a] not arrayOf

Author: jmagaram

src/Core__Array.mjs

@@ -140,9 +140,9 @@ function findMap(arr, f) {
 
 function fromOption(opt) {
   if (opt !== undefined) {
-    return Array.of(Caml_option.valFromOption(opt));
+    return [Caml_option.valFromOption(opt)];
   } else {
-    return Array.of();
+    return [];
   }
 }
 

src/Core__Array.res

@@ -215,11 +215,8 @@ let findMap = (arr, f) => {
 
 @send external at: (array<'a>, int) => option<'a> = "at"
 
-@val external of0: unit => array<'a> = "Array.of"
-@val external of1: 'a => array<'a> = "Array.of"
-
 let fromOption = opt =>
   switch opt {
-  | None => of0()
-  | Some(a) => of1(a)
+  | None => []
+  | Some(a) => [a]
   }