`class` prop type

[aabounegm]

After the last update in Sveld, it became possible to give @types to props defined via a rename export, enabling us to give a type to the class prop.

Caveats:

• In components where {...$$restProps} is used, an error will occur in the declaration file similar to the following:

  Interface 'BadgeProps' incorrectly extends interface 'HTMLAttributes<HTMLDivElement>'.
  Types of property 'class' are incompatible.
  Type 'string | false | null | undefined' is not assignable to type 'string | null | undefined'.
    Type 'false' is not assignable to type 'string | null | undefined'

  However, this should ultimately not affect the end user. On the contrary, allowing false values is a utility for users.

Additionally, this fixes many more type errors, which brings the actionable errors of svelte-check to a minimum (there are still a couple errors that we can fix, while the rest is out of our hand). Closes #333

[github-actions[bot]]

Docs available on https://illright.github.io/attractions/334/