fs: move chmod example to parent section

Author: roadev

doc/api/fs.md

@@ -1243,6 +1243,13 @@ possible exception are given to the completion callback.
 
 See also: chmod(2).
 
+```js
+fs.chmod('my_file.txt', 775, (err) => {
+  if (err) throw err;
+  console.log('The permissions for file "my_file.txt" have been changed!');
+});
+```
+
 ### File modes
 
 The `mode` argument used in both the `fs.chmod()` and `fs.chmodSync()`
@@ -1293,13 +1300,6 @@ Caveats: on Windows only the write permission can be changed, and the
 distinction among the permissions of group, owner or others is not
 implemented.
 
-```js
-fs.chmod('my_file.txt', 775, (err) => {
-  if (err) throw err;
-  console.log('The permissions for file "my_file.txt" have been changed!');
-});
-```
-
 ## fs.chmodSync(path, mode)
 <!-- YAML
 added: v0.6.7