Fix minor grammatical error in menu bar

The "us" in the "Help > Join us on Twitter" menu action should be capitalized to follow proper pronoun titling.

src/vs/workbench/electron-browser/actions.ts

@@ -1142,7 +1142,7 @@ export class ToggleWindowTabsBar extends Action {
 export class OpenTwitterUrlAction extends Action {
 
 	static readonly ID = 'workbench.action.openTwitterUrl';
-	static LABEL = nls.localize('openTwitterUrl', "Join us on Twitter", product.applicationName);
+	static LABEL = nls.localize('openTwitterUrl', "Join Us on Twitter", product.applicationName);
 
 	constructor(
 		id: string,

src/vs/workbench/electron-browser/main.contribution.ts

@@ -66,7 +66,7 @@ if (OpenTipsAndTricksUrlAction.AVAILABLE) {
 	workbenchActionsRegistry.registerWorkbenchAction(new SyncActionDescriptor(OpenTipsAndTricksUrlAction, OpenTipsAndTricksUrlAction.ID, OpenTipsAndTricksUrlAction.LABEL), 'Help: Tips and Tricks', helpCategory);
 }
 
-workbenchActionsRegistry.registerWorkbenchAction(new SyncActionDescriptor(OpenTwitterUrlAction, OpenTwitterUrlAction.ID, OpenTwitterUrlAction.LABEL), 'Help: Join us on Twitter', helpCategory);
+workbenchActionsRegistry.registerWorkbenchAction(new SyncActionDescriptor(OpenTwitterUrlAction, OpenTwitterUrlAction.ID, OpenTwitterUrlAction.LABEL), 'Help: Join Us on Twitter', helpCategory);
 workbenchActionsRegistry.registerWorkbenchAction(new SyncActionDescriptor(OpenRequestFeatureUrlAction, OpenRequestFeatureUrlAction.ID, OpenRequestFeatureUrlAction.LABEL), 'Help: Search Feature Requests', helpCategory);
 workbenchActionsRegistry.registerWorkbenchAction(new SyncActionDescriptor(OpenLicenseUrlAction, OpenLicenseUrlAction.ID, OpenLicenseUrlAction.LABEL), 'Help: View License', helpCategory);
 workbenchActionsRegistry.registerWorkbenchAction(new SyncActionDescriptor(OpenPrivacyStatementUrlAction, OpenPrivacyStatementUrlAction.ID, OpenPrivacyStatementUrlAction.LABEL), 'Help: Privacy Statement', helpCategory);
@@ -392,7 +392,7 @@ MenuRegistry.appendMenuItem(MenuId.MenubarHelpMenu, {
 	group: '3_feedback',
 	command: {
 		id: 'workbench.action.openTwitterUrl',
-		title: nls.localize({ key: 'miTwitter', comment: ['&& denotes a mnemonic'] }, "&&Join us on Twitter")
+		title: nls.localize({ key: 'miTwitter', comment: ['&& denotes a mnemonic'] }, "&&Join Us on Twitter")
 	},
 	order: 1
 });