Dead links in docs

[allan2]

There are dead unversioned links in the docs.

Examples:

• the link to "Yew Docs" on the html! docs https://docs.rs/yew/latest/yew/macro.html.html pointing to https://yew.rs/concepts/html/
• the link to "official documentation" in on the Tutorial page https://yew.rs/docs/next/tutorial pointing to https://yew.rs/docs/getting-started/project-setup/introduction