Peek or Preview Definitions Inline

[Sushisource]

I searched for existing issues for this but (to my surprise) didn't find one. Perhaps I didn't search very well, but "peek" and "preview" are the words I would associate with this. Apparently, after looking at the action name in JetBrains IDEs, they call it "Quick Definition", but what I'm looking for is something like this:

When the action is run, it shows an overlay of the definition of the thing under the cursor. This is really useful to give a quick look at something that might not be revealed by just the type signature / docstring without the weight of opening up a new tab. The overlay is quickly dismissed by pressing escape, or even moving the cursor.

This preview is internally scrollable in the JetBrains IDEs, (as well as VSCode, too, I believe). However I think VSCode's implementation is much less desirable, as it sort of "inlines" the preview, pushing subsequent lines in the buffer further down the screen rather than overlaying the peeked definition. I think this disrupts the user's sense of where they are in the file and is pretty undesirable. It also leads to an unpleasant "snapping" back to the original shape when the peek is dismissed.

Zed's a great project! Keep it up!