Update types so instance can be assigned to a variable of type Chart (#8525)

* Update types
* Remove outdated comments

types/scriptable.d.ts

@@ -1,4 +0,0 @@
-export type Scriptable<T, TContext> = T | ((ctx: TContext) => T);
-export type ScriptableOptions<T, TContext> = { [P in keyof T]: Scriptable<T[P], TContext> };
-export type ScriptableAndArray<T, TContext> = readonly T[] | Scriptable<T, TContext>;
-export type ScriptableAndArrayOptions<T, TContext> = { [P in keyof T]: ScriptableAndArray<T[P], TContext> };

types/tests/test_instance_assignment.ts

@@ -0,0 +1,20 @@
+import { Chart } from '../index.esm';
+
+const chart = new Chart('id', {
+  type: 'scatter',
+  data: {
+    labels: [],
+    datasets: [{
+      data: [],
+      pointRadius: (ctx) => ctx.parsed.x,
+    }]
+  },
+});
+
+interface Context {
+  chart: Chart;
+}
+
+export const ctx: Context = {
+  chart: chart
+};