doc: prepare js code for eslint-plugin-markdown

This is an initial step to eliminate most of parsing errors.

PR-URL: https://github.com/nodejs/node/pull/12563
Refs: https://github.com/nodejs/node/pull/12557#issuecomment-296015032
Reviewed-By: Teddy Katz <teddy.katz@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Timothy Gu <timothygu99@gmail.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>
Reviewed-By: Yuta Hiroto <hello@about-hiroppy.com>

2 files changed, 22 insertions, 22 deletions

diff --git a/doc/guides/using-internal-errors.md b/doc/guides/using-internal-errors.md
index 9f8634dc23..948a87612e 100644
--- a/doc/guides/using-internal-errors.md
+++ b/doc/guides/using-internal-errors.md
@@ -52,7 +52,7 @@ and appending the new error codes to the end using the utility `E()` method.
 
 ```js
 E('EXAMPLE_KEY1', 'This is the error value');
-E('EXAMPLE_KEY2', (a, b) => return `${a} ${b}`);
+E('EXAMPLE_KEY2', (a, b) => `${a} ${b}`);
 ```
 
 The first argument passed to `E()` is the static identifier. The second
diff --git a/doc/guides/writing-tests.md b/doc/guides/writing-tests.md
index d0a6e1a199..70690e2fda 100644
--- a/doc/guides/writing-tests.md
+++ b/doc/guides/writing-tests.md
@@ -23,27 +23,27 @@ Add tests when:
 Let's analyze this basic test from the Node.js test suite:
 
 ```javascript
-1   'use strict';
-2   const common = require('../common');
-3
-4   // This test ensures that the http-parser can handle UTF-8 characters
-5   // in the http header.
-6
-7   const assert = require('assert');
-8   const http = require('http');
-9
-10  const server = http.createServer(common.mustCall((req, res) => {
-11    res.end('ok');
-12  }));
-13  server.listen(0, () => {
-14   http.get({
-15     port: server.address().port,
-16     headers: {'Test': 'Düsseldorf'}
-17   }, common.mustCall((res) => {
-18     assert.strictEqual(res.statusCode, 200);
-19     server.close();
-20   }));
-21 });
+'use strict';                                                          // 1
+const common = require('../common');                                   // 2
+                                                                       // 3
+// This test ensures that the http-parser can handle UTF-8 characters  // 4
+// in the http header.                                                 // 5
+                                                                       // 6
+const assert = require('assert');                                      // 7
+const http = require('http');                                          // 8
+                                                                       // 9
+const server = http.createServer(common.mustCall((req, res) => {       // 10
+  res.end('ok');                                                       // 11
+}));                                                                   // 12
+server.listen(0, () => {                                               // 13
+  http.get({                                                           // 14
+    port: server.address().port,                                       // 15
+    headers: {'Test': 'Düsseldorf'}                                    // 16
+  }, common.mustCall((res) => {                                        // 17
+    assert.strictEqual(res.statusCode, 200);                           // 18
+    server.close();                                                    // 19
+  }));                                                                 // 20
+});                                                                    // 21
 ```
 
 ### **Lines 1-2**