fix(CSS): add :host, :host-context, and ::slotted selector examples

[OnkarRuikar]

• Adds examples for selector page needs a try it section content#27938

To test checkout the branch in local then run

npm install
npm run build
npm start

Open following URLs in browser:

http://localhost:9090/pages/tabbed/pseudo-class-host.html
http://localhost:9090/pages/tabbed/pseudo-class-host_function.html
http://localhost:9090/pages/tabbed/pseudo-class-host-context.html
http://localhost:9090/pages/tabbed/pseudo-element-slotted.html

[Rumyra]

Thanks @OnkarRuikar - these look great :D

[NiedziolkaMichal]

Too bad I created similar examples more than a year ago and they were never reviewed: #2177 #2186
I will close those PRs.

[OnkarRuikar]

Too bad I created similar examples more than a year ago and they were never reviewed: #2177 #2186 I will close those PRs.

😰 I should've looked for existing PRs first. Never though something that old would already exist.

[sideshowbarker]

Too bad I created similar examples more than a year ago and they were never reviewed: #2177 #2186
I will close those PRs.

Please don't close them. I have been reviewing and merging the open PRs here, and I plan to get all of them merged soon.