Add scrollbar for large snippet tooltip

[ecool]

Some snippets are very large and the tooltip extends to fill the screen. Maybe set a configurable setting for max tooltip height and add a scrollbar to it whenever it hits that size or is larger than the height of the screen.

Should be possible to do with setting overflow on the tooltip div and setting a max-height through a CSS style.

div {
    overflow-y: auto;
    max-height: 100%;
}

May need to do so for width as well with overflow: auto; and setting both max-height and max-width.

[RandomFractals]

We might have to log this in vscode repo since that snippet tree view uses TreeItem tooltip provided by vscode api.

Unless I find CSS class name used for setting that vscode tooltip, I will not be able to fix it with max width, height and overflow on my end.

[ecool]

I'm currently looking at a possible way to override/include a custom style into the MarkdownString.

[ecool]

Apparently, MarkdownString or however the tooltip is constructed and shown to the user ignores