doc: add await to browser.close in usage examples (#797)

browser.close returns a promise after f398e69, so it should be awaited.

examples/block-images.js

@@ -32,7 +32,7 @@ page.on('request', request => {
 await page.goto('https://www.reuters.com/');
 await page.screenshot({path: 'news.png', fullPage: true});
 
-browser.close();
+await browser.close();
 
 })();
 

examples/custom-event.js

@@ -45,6 +45,6 @@ await listenFor('app-ready'); // Listen for "app-ready" custom event on page loa
 
 await page.goto('https://www.chromestatus.com/features', {waitUntil: 'networkidle'});
 
-browser.close();
+await browser.close();
 
 })();

examples/detect-sniff.js

@@ -41,6 +41,6 @@ await page.evaluateOnNewDocument(sniffDetector);
 await page.goto('https://www.google.com', {waitUntil: 'networkidle'});
 console.log('Sniffed: ' + (await page.evaluate(() => !!navigator.sniffed)));
 
-browser.close();
+await browser.close();
 
 })();

examples/pdf.js

@@ -30,6 +30,6 @@ await page.pdf({
   format: 'letter'
 });
 
-browser.close();
+await browser.close();
 
 })();

examples/proxy.js

@@ -28,6 +28,6 @@ const browser = await puppeteer.launch({
 });
 const page = await browser.newPage();
 await page.goto('https://google.com');
-browser.close();
+await browser.close();
 
 })();

examples/screenshot-fullpage.js

@@ -26,6 +26,6 @@ const page = await browser.newPage();
 await page.emulate(devices['iPhone 6']);
 await page.goto('https://www.nytimes.com/');
 await page.screenshot({path: 'full.png', fullPage: true});
-browser.close();
+await browser.close();
 
 })();

examples/screenshot.js

@@ -25,6 +25,6 @@ const page = await browser.newPage();
 await page.goto('http://example.com');
 await page.screenshot({path: 'example.png'});
 
-browser.close();
+await browser.close();
 
 })();

examples/search.js

@@ -37,6 +37,6 @@ const links = await page.evaluate(() => {
   return anchors.map(anchor => anchor.textContent);
 });
 console.log(links.join('\n'));
-browser.close();
+await browser.close();
 
 })();