Support referencing context key values in window.title template

[hediet]

Currently, window.title allows several variables.
It would be awesome for extensibility, if ${context.myContextVar} would be supported, with myContextVar being an arbitrary context variable.

Then extensions could contribute to the window title (candidates would be ${context.debuggerStateEmoji} or ${context.workspaceEmoji}).

I'd be up to create a PR!

Related: #2809

[bpasero]

Sounds interesting, feel free to give it a try. The variables are substituted from here:

vscode/src/vs/workbench/browser/parts/titlebar/windowTitle.ts

Lines 287 to 288 in 8baf105

	// Variables
	const activeEditorShort = editor ? editor.getTitle(Verbosity.SHORT) : '';

[LEKPHET-KUNSUE]

anyone assign me pls

[benibenj]

Verification steps:

1. From an extension, create a contxt key and register a title variable

export function activate(context: vscode.ExtensionContext) {
    setInterval(() => 
        vscode.commands.executeCommand('setContext', 'timeNowContextKey', new Date().toLocaleTimeString()),
        1000
    );
    vscode.commands.executeCommand('registerWindowTitleVariable', 'timeNow', 'timeNowContextKey');
}

2. go to window.title in settings and add the newly created title variable (for example window.title: "${timeNow}")
3. Make sure the window title correctly renders the value of the variable in the command center / window title area