docs(examples): Anchor for each example

#### Documentation Feedback

Hi, it would be great if "Examples" pages had anchors like "Overview" and "API" has.
I often find myself sending colleagues links for example pages and saying search for "List with sections" and so on. The other two pages have this feature and it's quite useful.

**Affected documentation page:** Every `http‎s://material.angular.io/components/**/examples`
