Add documentation metadata and overloads for distinct API

[zaleslaw]

Fixes #817

[Jolanrensen]

I experimented a bit with a @see href template. What do you think about something like this?

/** https://kotlin.github.io/dataframe */
interface Url

/** @see <a href="{@include [Url]}/$[URL_PART]">See $[NAME]=this on the documentation website.</a> */
private interface SeeTag {
    // The part after the base url, if not supplied, it defaults to the base url
    interface URL_PART

    // The name of the concept the user will see in the @see link, defaults to "this"
    interface NAME
}

...

/** @include [SeeTag] {@set [SeeTag.URL_PART] distinct.html}{@set [SeeTag.NAME] `distinct`} */
interface SeeDistinctDocumentation

I've included the "@see" part in the doc interface, because <a href ... does not render outside @see. WDYT?

[zaleslaw]

@Jolanrensen let's make common refactoring of URls/See tag support as a separate PR

[Jolanrensen]

@zaleslaw you forgot the linter + apiDump. The TC build fails.

You can suppress the argument name by putting @Suppress("ClassName") next to your DistinctDocs interface.

[zaleslaw]

Thanks @Jolanrensen will fix soon