refactor(material/progress-spinner): deprecate MatSpinner (#26108)

* refactor(material/progress-spinner): deprecate MatSpinner

* fixup! refactor(material/progress-spinner): deprecate MatSpinner

(cherry picked from commit 2477539)

Author: wagnermaciel

src/material/progress-spinner/progress-spinner.ts

@@ -198,10 +198,9 @@ export class MatProgressSpinner extends _MatProgressSpinnerBase implements CanCo
 }
 
 /**
- * `<mat-spinner>` component.
- *
- * This is a component definition to be used as a convenience reference to create an
- * indeterminate `<mat-progress-spinner>` instance.
+ * @deprecated Import Progress Spinner instead. Note that the
+ *    `mat-spinner` selector isn't deprecated.
+ * @breaking-change 16.0.0
  */
 // tslint:disable-next-line:variable-name
 export const MatSpinner = MatProgressSpinner;

tools/public_api_guard/material/progress-spinner.md

@@ -62,7 +62,7 @@ export class MatProgressSpinnerModule {
     static ɵmod: i0.ɵɵNgModuleDeclaration<MatProgressSpinnerModule, [typeof i1.MatProgressSpinner, typeof i1.MatProgressSpinner], [typeof i2.CommonModule], [typeof i1.MatProgressSpinner, typeof i1.MatProgressSpinner, typeof i3.MatCommonModule]>;
 }
 
-// @public
+// @public @deprecated (undocumented)
 export const MatSpinner: typeof MatProgressSpinner;
 
 // @public