In the `docs-watch` job we attempt to guess what additional files need
to be processed given a change to a single file. Previously we were not
finding links to examples that were defined over multiple lines. E.g.
```
<code-pane
header="src/app/app.component.html"
region="hero-birthday-template"
path="pipes/src/app/app.component.html">
</code-pane>
```
This commit improves the regular expression to handle these cases.
PR Close#40479
Pete Bacon Darwin