Improve hover feedback for insert toolbar

[rebornix]

While testing microsoft/vscode-jupyter#10598, I was following a blog post to test ipywidgets, my workflow is more or less

• have two browser pages side by side
• copy code from the blog post
• hover on the end of the notebook document in vscode.dev, move around to trigger the insert toolbar to show up, click the + code button and then paste code into it
• click the run button

Hover to show the insert toolbar is hard, I don't have confidence that I can have it to show up easily so at the end I started to use keyboard shortcut. I tried to do the same with Google Colab and found myself more successful in inserting cells through the insert toolbar.

[roblourens]

Is this specifically about the one at the end of the document, like when you scroll into empty space?

[rebornix]

@roblourens not necessarily the last one, I have a bit trouble hovering on all insert cell toolbars. Colab one feels more responsive to me.

[roblourens]

Any idea what is different or why it feels that way?

[roblourens]

Can revisit this if we have something concrete