Fix small typo

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

@@ -181,7 +181,7 @@ let workbenchProperties: { [path: string]: IJSONSchema; } = {
 	},
 	'workbench.commandPalette.history': {
 		'type': 'number',
-		'description': nls.localize('commandHistory', "Controls if the number of recently used commands to keep in history for the command palette. Set to 0 to disable command history."),
+		'description': nls.localize('commandHistory', "Controls the number of recently used commands to keep in history for the command palette. Set to 0 to disable command history."),
 		'default': 50
 	},
 	'workbench.commandPalette.preserveInput': {
@@ -438,4 +438,4 @@ configurationRegistry.registerConfiguration({
 			'description': nls.localize('zenMode.restore', "Controls if a window should restore to zen mode if it was exited in zen mode.")
 		}
 	}
-});
\ No newline at end of file
+});