Test: ExtensionContext.environmentVariableCollection UX

[Tyriar]

Refs: #46696, #95573

• macOS @chrisdias
• Windows @gregvanl

Complexity: 3

---

The UX side of this API is done. An extension can contribute environment changes to terminals via this API:

vscode/src/vs/vscode.proposed.d.ts

Lines 1047 to 1053 in 686ad17

	export interface ExtensionContext {
	/**
	* Gets the extension's environment variable collection for this workspace, enabling changes
	* to be applied to terminal environment variables.
	*/
	readonly environmentVariableCollection: EnvironmentVariableCollection;
	}

The API itself was tested last month, this month focus on the UX side of things with the indicator that appears in the top-right of each terminal, the hover and the relaunch terminal command.

Use the Update Environment and Clear Environment commands in this extension as a place to start: https://github.com/microsoft/vscode-extension-samples/tree/master/terminal-sample

[gregvanl]

Just a testing note on Windows. Noodling around relaunching terminal may hang the editor due to #76548