doc: fix code examples in zlib.md

* Use test() instead of match() in boolean context.
* Add spaces in code example.
* Fix typo.

PR-URL: #13342
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>

doc/api/zlib.md

@@ -102,10 +102,10 @@ http.createServer((request, response) => {
 
   // Note: This is not a conformant accept-encoding parser.
   // See http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.3
-  if (acceptEncoding.match(/\bdeflate\b/)) {
+  if (/\bdeflate\b/.test(acceptEncoding)) {
     response.writeHead(200, { 'Content-Encoding': 'deflate' });
     raw.pipe(zlib.createDeflate()).pipe(response);
-  } else if (acceptEncoding.match(/\bgzip\b/)) {
+  } else if (/\bgzip\b/.test(acceptEncoding)) {
     response.writeHead(200, { 'Content-Encoding': 'gzip' });
     raw.pipe(zlib.createGzip()).pipe(response);
   } else {
@@ -119,15 +119,15 @@ By default, the `zlib` methods will throw an error when decompressing
 truncated data. However, if it is known that the data is incomplete, or
 the desire is to inspect only the beginning of a compressed file, it is
 possible to suppress the default error handling by changing the flushing
-method that is used to compressed the last chunk of input data:
+method that is used to decompress the last chunk of input data:
 
 ```js
 // This is a truncated version of the buffer from the above examples
 const buffer = Buffer.from('eJzT0yMA', 'base64');
 
 zlib.unzip(
   buffer,
-  {finishFlush: zlib.constants.Z_SYNC_FLUSH},
+  { finishFlush: zlib.constants.Z_SYNC_FLUSH },
   (err, buffer) => {
     if (!err) {
       console.log(buffer.toString());