Rename "Raindrop" to "Bookmark"

[phildenhoff]

While Raindrop's API says that the object that is a URL, title, highlights (each with a possible note) is called a "Raindrop", it's much more commonly called a Bookmark on their website.

To avoid confusion, let's move to the term shown to users: bookmark. We can rename anything called Raindrop to Bookmark and change any user facing text to read Bookmark.

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Here's a few examples of "bookmark"

And here are the examples I could find where they call them "Raindrops":

...

There were none.