feat(module:tree-select): support TemplateRef type for nzNotFoundContent (#8638)

fix #8631

Co-authored-by: OriginRing <wb-gyy965916@alibaba-inc.com>

Author: OriginRing

components/tree-select/demo/module

@@ -3,6 +3,6 @@ import { NzIconModule } from 'ng-zorro-antd/icon';
 import { FormsModule } from '@angular/forms';
 import { NzRadioModule } from 'ng-zorro-antd/radio';
 import { NzSpaceModule } from 'ng-zorro-antd/space';
+import { NzSpinModule } from 'ng-zorro-antd/spin';
 
-
-export const moduleList = [ FormsModule, NzTreeSelectModule, NzIconModule , NzRadioModule , NzSpaceModule];
+export const moduleList = [ FormsModule, NzTreeSelectModule, NzIconModule , NzRadioModule , NzSpaceModule, NzSpinModule];

components/tree-select/demo/no-data.md

@@ -0,0 +1,15 @@
+---
+order: 7
+title:
+  zh-CN: 自定义空状态
+  en-US: Custom empty state
+---
+
+## zh-CN
+
+使用 `nzNotFoundContent` 自定义空数据状态
+
+## en-US
+
+Use `nzNotFoundContent` to customize empty data style
+

components/tree-select/demo/no-data.ts

@@ -0,0 +1,23 @@
+import { Component } from '@angular/core';
+
+@Component({
+  selector: 'nz-demo-tree-select-no-data',
+  template: `
+    <nz-tree-select
+      style="width: 250px"
+      [nzNodes]="nodes"
+      nzPlaceHolder="Please select"
+      [(ngModel)]="value"
+      [nzNotFoundContent]="noData"
+    ></nz-tree-select>
+    <ng-template #noData>
+      <div style="height: 200px; display: flex; justify-content: center; align-items: center">
+        <nz-spin nzSimple> </nz-spin>
+      </div>
+    </ng-template>
+  `
+})
+export class NzDemoTreeSelectNoDataComponent {
+  value?: string;
+  nodes = [];
+}

components/tree-select/demo/placement.md

@@ -1,5 +1,5 @@
 ---
-order: 7
+order: 8
 title:
   zh-CN: 位置
   en-US: Placement

components/tree-select/demo/status.md

@@ -1,5 +1,5 @@
 ---
-order: 8
+order: 9
 title:
   zh-CN: 自定义状态
   en-US: Status

components/tree-select/doc/index.en-US.md

@@ -275,7 +275,7 @@ export class NzTreeSelectComponent extends NzTreeBase implements ControlValueAcc
   @Input() nzVirtualMinBufferPx = 28;
   @Input() nzVirtualHeight: string | null = null;
   @Input() nzExpandedIcon?: TemplateRef<{ $implicit: NzTreeNode; origin: NzTreeNodeOptions }>;
-  @Input() nzNotFoundContent?: string;
+  @Input() nzNotFoundContent?: string | TemplateRef<void>;
   @Input() nzNodes: NzTreeNodeOptions[] | NzTreeNode[] = [];
   @Input() nzOpen = false;
   @Input() @WithConfig() nzSize: NzSizeLDSType = 'default';