docs: remove await from chrome.kill() (#15982)

Co-authored-by: Connor Clark <cjamcl@gmail.com>

docs/headless-chrome.md

@@ -101,8 +101,10 @@ const chromeLauncher = require('chrome-launcher');
 function launchChromeAndRunLighthouse(url, flags = {}, config = null) {
   return chromeLauncher.launch(flags).then(chrome => {
     flags.port = chrome.port;
-    return lighthouse(url, flags, config).then(results =>
-      chrome.kill().then(() => results));
+    return lighthouse(url, flags, config).then(results => {
+      chrome.kill();
+      return results;
+    }
   });
 }
 

docs/puppeteer.md

@@ -73,5 +73,5 @@ const {lhr}  = await lighthouse(url, undefined, undefined, page);
 console.log(`Lighthouse scores: ${Object.values(lhr.categories).map(c => c.score).join(', ')}`);
 
 await browser.disconnect();
-await chrome.kill();
+chrome.kill();
 ```

docs/readme.md

@@ -24,7 +24,7 @@ fs.writeFileSync('lhreport.html', reportHtml);
 console.log('Report is done for', runnerResult.lhr.finalDisplayedUrl);
 console.log('Performance score was', runnerResult.lhr.categories.performance.score * 100);
 
-await chrome.kill();
+chrome.kill();
 ```
 
 ### Performance-only Lighthouse run