fix(tooltip): Updating the aria label of the tooltip buttons.

Author: MartinKamenov

src/material-examples/tooltip-manual/tooltip-manual-example.html

@@ -2,19 +2,19 @@
   <span> Click the following buttons to... </span>
   <button mat-button
           (click)="tooltip.show()"
-          aria-label="Button that progamatically shows a tooltip on another button"
+          aria-label="Show tooltip on the button at the end of this section"
           class="example-action-button">
     show
   </button>
   <button mat-button
           (click)="tooltip.hide()"
-          aria-label="Button that progamatically hides a tooltip on another button"
+          aria-label="Hide tooltip on the button at the end of this section"
           class="example-action-button">
     hide
   </button>
   <button mat-button
           (click)="tooltip.toggle()"
-          aria-label="Button that progamatically toggles a tooltip on another button to show/hide"
+          aria-label="Show/Hide tooltip on the button at the end of this section"
           class="example-action-button">
     toggle show/hide
   </button>