chore: equality + doc cleanups

Author: BenHenning

core/focus_manager.ts

@@ -224,7 +224,7 @@ export class FocusManager {
    */
   focusNode(focusableNode: IFocusableNode): void {
     this.ensureManagerIsUnlocked();
-    if (this.focusedNode == focusableNode) return; // State is unchanged.
+    if (this.focusedNode === focusableNode) return; // State is unchanged.
 
     const nextTree = focusableNode.getFocusableTree();
     if (!this.isRegistered(nextTree)) {

core/interfaces/i_focusable_node.ts

@@ -32,7 +32,7 @@ export interface IFocusableNode {
    *
    * It's expected the actual returned element will not change for the lifetime
    * of the node (that is, its properties can change but a new element should
-   * never be returned.)
+   * never be returned).
    */
   getFocusableElement(): HTMLElement | SVGElement;
 

core/interfaces/i_focusable_tree.ts

@@ -39,7 +39,7 @@ export interface IFocusableTree {
 
   /**
    * Returns the IFocusableNode of this tree that should receive active focus
-   * when the tree itself has focused returned to it.
+   * when the tree itself has focus returned to it.
    *
    * There are some very important notes to consider about a tree's focus
    * lifecycle when implementing a version of this method that doesn't return