chore: Renamed 'DependableTrait' to new name 'Dependable' (#1087)

It looks like the former Name of 'Dependable' was 'DependableTrait'. Latter name is mentioned in the code documentation, which doesn't fit to the code anymore. I updated the docs regarding the current code.
Fixes #1093

Author: ThomasSteinbach

API.md

@@ -470,7 +470,7 @@ __Implemented by__: [Construct](#constructs-construct), [DependencyGroup](#const
 Trait marker for classes that can be depended upon.
 
 The presence of this interface indicates that an object has
-an `IDependableTrait` implementation.
+an `IDependable` implementation.
 
 This interface can be used to take an (ordering) dependency on a set of
 constructs. An ordering dependency implies that the resources represented by

src/dependency.ts

@@ -4,7 +4,7 @@ import { IConstruct } from './construct';
  * Trait marker for classes that can be depended upon
  *
  * The presence of this interface indicates that an object has
- * an `IDependableTrait` implementation.
+ * an `IDependable` implementation.
  *
  * This interface can be used to take an (ordering) dependency on a set of
  * constructs. An ordering dependency implies that the resources represented by
@@ -64,11 +64,11 @@ const DEPENDABLE_SYMBOL = Symbol.for('@aws-cdk/core.DependableTrait');
  * @example
  *
  * // Usage
- * const roots = DependableTrait.get(construct).dependencyRoots;
+ * const roots = Dependable.of(construct).dependencyRoots;
  *
  * // Definition
- * DependableTrait.implement(construct, {
- *   get dependencyRoots() { return []; }
+ * Dependable.implement(construct, {
+ *       dependencyRoots: [construct],
  * });
  *
  * @experimental