message: docs: fix links to Material examples
  Also uses fixed git hashes so the line numbers won't get outdated in the
  future
  PR Close
diff: @@ -70,7 +70,7 @@ When authoring Angular components, you should re-use these native elements direc
  For example, instead of creating a custom element for a new variety of button, you can create a component that uses an attribute selector with a native `<button>` element.
  This most commonly applies to `<button>` and `<a>`, but can be used with many other types of element.
  -You can see examples of this pattern in Angular Material: [`MatButton`](https://github.com/angular/components/blob/master/src/material/button/button.ts#L66-L68), [`MatTabNav`](https://github.com/angular/components/blob/master/src/material/tabs/tab-nav-bar/tab-nav-bar.ts#L67), [`MatTable`](https://github.com/angular/components/blob/master/src/material/table/table.ts#L17).
  +You can see examples of this pattern in Angular Material: [`MatButton`](https://github.com/angular/components/blob/50d3f29b6dc717b512dbd0234ce76f4ab7e9762a/src/material/button/button.ts#L67-L69), [`MatTabNav`](https://github.com/angular/components/blob/50d3f29b6dc717b512dbd0234ce76f4ab7e9762a/src/material/tabs/tab-nav-bar/tab-nav-bar.ts#L139), [`MatTable`](https://github.com/angular/components/blob/50d3f29b6dc717b512dbd0234ce76f4ab7e9762a/src/material/table/table.ts#L22).
  ### Using containers for native elements
  