fix(cdk/tree): remove NB: comments

src/cdk/a11y/key-manager/tree-key-manager.ts

@@ -142,7 +142,7 @@ export class TreeKeyManager<T extends TreeKeyManagerItem> implements TreeKeyMana
 
     switch (key) {
       case 'Tab':
-        // NB: return here, in order to allow Tab to actually tab out of the tree
+        // Return early here, in order to allow Tab to actually tab out of the tree
         return;
 
       case 'ArrowDown':

src/cdk/tree/tree.ts

@@ -382,7 +382,7 @@ export class CdkTree<T, K = T>
     this._dataSubscription = combineLatest([
       dataStream,
       this._nodeType,
-      // NB: the data is unused below, however we add it here to essentially
+      // We don't use the expansion data directly, however we add it here to essentially
       // trigger data rendering when expansion changes occur.
       expansionModel.changed.pipe(
         startWith(null),
@@ -955,8 +955,8 @@ export class CdkTree<T, K = T>
    * nodes into a single array.
    *
    * If any nodes are not expanded, then their children will not be added into the array.
-   * NB: this will still traverse all nested children in order to build up our
-   * internal data models, but will not include them in the returned array.
+   * This will still traverse all nested children in order to build up our internal data
+   * models, but will not include them in the returned array.
    */
   private _flattenNestedNodesWithExpansion(nodes: readonly T[], level = 0): Observable<T[]> {
     const childrenAccessor = this._getChildrenAccessor();

src/components-examples/cdk/tree/cdk-tree-custom-key-manager/cdk-tree-custom-key-manager-example.ts

@@ -167,7 +167,7 @@ export class VimTreeKeyManager<T extends TreeKeyManagerItem> implements TreeKeyM
 
     switch (keyCode) {
       case TAB:
-        // NB: return here, in order to allow Tab to actually tab out of the tree
+        // Return early here, in order to allow Tab to actually tab out of the tree
         return;
 
       case DOWN_ARROW:

src/material/tree/tree-using-tree-control.spec.ts

@@ -457,7 +457,7 @@ describe('MatTree', () => {
         (getNodes(treeElement)[1] as HTMLElement).click();
         fixture.detectChanges();
 
-        // NB: only four elements are present here; children are not present
+        // Note: only four elements are present here; children are not present
         // in DOM unless the parent node is expanded.
         expect(
           getNodes(treeElement)

src/material/tree/tree.spec.ts

@@ -444,7 +444,7 @@ describe('MatTree', () => {
         (getNodes(treeElement)[1] as HTMLElement).click();
         fixture.detectChanges();
 
-        // NB: only four elements are present here; children are not present
+        // Note: only four elements are present here; children are not present
         // in DOM unless the parent node is expanded.
         expect(
           getNodes(treeElement)