fix(datagrid): update datagrid virtual scroll selector name (#1700)

## PR Checklist

Please check if your PR fulfills the following requirements:

- [ ] Tests for the changes have been added (for bug fixes / features)
- [ ] Docs have been added / updated (for bug fixes / features)
- [ ] If applicable, have a visual design approval

## PR Type

What kind of change does this PR introduce?

- [x] Bugfix
- [ ] Feature
- [ ] Code style update (formatting, local variables)
- [ ] Refactoring (no functional changes, no api changes)
- [ ] Build related changes
- [ ] CI related changes
- [ ] Documentation content changes
- [ ] Other... Please describe:

## What is the current behavior?
Current virtual scroll selector follow `Pascal Case` pattern.

Issue Number: N/A

## What is the new behavior?
Virtual scroll selector follow `Camel Case` pattern.
The original `Pascal Case` pattern is still supported, but deprecated.

## Does this PR introduce a breaking change?

- [ ] Yes
- [x] No

## Other information

.storybook/stories/datagrid/datagrid-virtualscroll-detail.stories.ts

@@ -110,7 +110,7 @@ const DatagridDetailsTemplate: StoryFn = args => ({
 
       <ng-template
         *ngIf="data.elements"
-        ClrVirtualScroll
+        clrVirtualScroll
         let-element
         let-index="index"
         [clrVirtualRowsOf]="data.elements"

.storybook/stories/datagrid/datagrid-virtualscroll.stories.ts

@@ -111,7 +111,7 @@ const DatagridTemplate: StoryFn = args => ({
 
       <ng-template
         *ngIf="data.elements"
-        ClrVirtualScroll
+        clrVirtualScroll
         let-element
         let-index="index"
         [clrVirtualRowsOf]="data.elements"

projects/angular/clarity.api.md

@@ -5855,7 +5855,7 @@ export class ÇlrDatagridVirtualScrollDirective<T> implements AfterViewInit, DoC
     // (undocumented)
     renderedRangeChange: EventEmitter<ListRange>;
     // (undocumented)
-    static ɵdir: i0.ɵɵDirectiveDeclaration<ÇlrDatagridVirtualScrollDirective<any>, "[ClrVirtualScroll]", never, { "cdkVirtualForOf": "clrVirtualRowsOf"; "cdkVirtualForTrackBy": "clrVirtualRowsTrackBy"; "cdkVirtualForTemplate": "clrVirtualRowsTemplate"; "cdkVirtualForTemplateCacheSize": "clrVirtualRowsTemplateCacheSize"; "itemSize": "clrVirtualRowsItemSize"; "minBufferPx": "clrVirtualRowsMinBufferPx"; "maxBufferPx": "clrVirtualRowsMaxBufferPx"; }, { "renderedRangeChange": "renderedRangeChange"; }, never, never, false, never>;
+    static ɵdir: i0.ɵɵDirectiveDeclaration<ÇlrDatagridVirtualScrollDirective<any>, "[clrVirtualScroll],[ClrVirtualScroll]", never, { "cdkVirtualForOf": "clrVirtualRowsOf"; "cdkVirtualForTrackBy": "clrVirtualRowsTrackBy"; "cdkVirtualForTemplate": "clrVirtualRowsTemplate"; "cdkVirtualForTemplateCacheSize": "clrVirtualRowsTemplateCacheSize"; "itemSize": "clrVirtualRowsItemSize"; "minBufferPx": "clrVirtualRowsMinBufferPx"; "maxBufferPx": "clrVirtualRowsMaxBufferPx"; }, { "renderedRangeChange": "renderedRangeChange"; }, never, never, false, never>;
     // (undocumented)
     static ɵfac: i0.ɵɵFactoryDeclaration<ÇlrDatagridVirtualScrollDirective<any>, [null, null, { skipSelf: true; }, null, null, null, null, null, null, null, null, null, null]>;
 }

projects/angular/src/data/datagrid/datagrid-virtual-scroll.directive.spec.ts

@@ -51,7 +51,7 @@ export interface Cells {
 
       <ng-template
         *ngIf="data.rows"
-        ClrVirtualScroll
+        clrVirtualScroll
         let-row
         [clrVirtualRowsOf]="data.rows"
         [clrVirtualRowsItemSize]="24"

projects/angular/src/data/datagrid/datagrid-virtual-scroll.directive.ts

@@ -66,7 +66,7 @@ const defaultCdkFixedSizeVirtualScrollInputs: CdkFixedSizeVirtualScrollInputs =
 };
 
 @Directive({
-  selector: '[ClrVirtualScroll]',
+  selector: '[clrVirtualScroll],[ClrVirtualScroll]',
   providers: [Items],
 })
 export class ClrDatagridVirtualScrollDirective<T> implements AfterViewInit, DoCheck, OnDestroy {

projects/demo/src/app/datagrid/virtual-scroll-client-side/virtual-scroll-client-side.html

@@ -47,7 +47,7 @@ <h3>Dynamic cols and rows</h3>
 
   <ng-template
     *ngIf="data.rows"
-    ClrVirtualScroll
+    clrVirtualScroll
     let-row
     [clrVirtualRowsOf]="data.rows"
     [clrVirtualRowsItemSize]="24"
@@ -95,7 +95,7 @@ <h3>Dynamic rows with sorting</h3>
 
   <ng-template
     *ngIf="data.users"
-    ClrVirtualScroll
+    clrVirtualScroll
     let-user
     [clrVirtualRowsOf]="data.users"
     [clrVirtualRowsItemSize]="32"

projects/demo/src/app/datagrid/virtual-scroll-server-side/virtual-scroll-server-side.html

@@ -42,7 +42,7 @@ <h2>Virtual scroll server side</h2>
 
   <ng-template
     *ngIf="data.users"
-    ClrVirtualScroll
+    clrVirtualScroll
     let-user
     [clrVirtualRowsOf]="data.users"
     [clrVirtualRowsItemSize]="24"