fix strict null errors

src/vs/editor/contrib/format/formatActions.ts

@@ -491,7 +491,7 @@ CommandsRegistry.registerCommand('editor.action.formatInspect', accessor => {
 
 	const editor = accessor.get(ICodeEditorService).getActiveCodeEditor();
 	if (!editor || !editor.hasModel()) {
-		return undefined;
+		return;
 	}
 	console.log(`Available Formatters for: ${editor.getModel().uri.toString(true)}`);
 	// range formatters

src/vs/platform/opener/common/opener.ts

@@ -23,5 +23,5 @@ export interface IOpenerService {
 
 export const NullOpenerService: IOpenerService = Object.freeze({
 	_serviceBrand: undefined,
-	open() { return Promise.resolve(undefined); }
+	open() { return Promise.resolve(false); }
 });

src/vs/workbench/parts/snippets/electron-browser/configureSnippets.ts

@@ -187,7 +187,7 @@ async function createLanguageSnippetFile(pick: ISnippetPick, fileService: IFileS
 	await fileService.updateContent(URI.file(pick.filepath), contents);
 }
 
-CommandsRegistry.registerCommand(id, async accessor => {
+CommandsRegistry.registerCommand(id, async (accessor): Promise<any> => {
 
 	const snippetService = accessor.get(ISnippetsService);
 	const quickInputService = accessor.get(IQuickInputService);