Test ThemeIcon color API in trees

[alexr00]

Refs: #103120

• macOS @jrieken
• linux @aeschli
• windows @isidorn

Complexity: 3

Create Issue

---

We have new API for coloring codicons:

vscode/src/vs/vscode.d.ts

Lines 826 to 827 in 35c3949

	constructor(id: string, color?: ThemeColor);
	}

Starting with the tree sample, use the new API to try changing icon colors in the tree. For example, try using a ThemeIcon here:

https://github.com/microsoft/vscode-extension-samples/blob/7b9a0a8c4c631e393862c3e767c7be26bb2233b2/tree-view-sample/src/jsonOutline.ts#L125-L126

Things to verify:

• Verify that the ThemeIcon color works (tree only).
• Verify that the documentation for the API makes sense.