TreeItem markdown string tooltip overflow needs scrollbars

[RandomFractals]

• VS Code Version: v1.54
• OS Version: win

Steps to Reproduce:

1. Install Snippets Viewer extension: https://marketplace.visualstudio.com/items?itemName=RandomFractalsInc.snippets-viewer
2. Install some extensions with snippets that have a body longer than a page of code
3. Mouse over a snippet with long code body in Snippets Viewer tree view

Problem:

Snippets Viewer uses vscode TreeItem with MarkdownString tooltips. That extension displays snippet prefix, description and full snippet body in TreeItem tooltip for preview. For long snippet bodies, TreeItem tooltip will need scrollbars added and overflow set on that UI element to see full snippet body in a tooltip.

Example:

This is from: RandomFractals/vscode-snippets-viewer#24

[vscodebot]

(Experimental duplicate detection)
Thanks for submitting this issue. Please also check if it is already covered by an existing one, like:

• [json] don't suggest top level snippet if there's already an object (#53454)
• Save highlighted code as snippet (#74711)
• Support allowlisting of snippets from extensions (#109705)

[Tyriar]

/duplicate #111608