updated docs regarding testSequencer (#9174)

Author: saiumesh535

docs/Configuration.md

@@ -1085,6 +1085,7 @@ Example:
 Sort test path alphabetically.
 
 ```js
+// testSequencer.js
 const Sequencer = require('@jest/test-sequencer').default;
 
 class CustomSequencer extends Sequencer {
@@ -1099,6 +1100,14 @@ class CustomSequencer extends Sequencer {
 module.exports = CustomSequencer;
 ```
 
+Use it in your Jest config file like this:
+
+```json
+{
+  "testSequencer": "path/to/testSequencer.js"
+}
+```
+
 ### `testTimeout` [number]
 
 Default: `5000`

website/versioned_docs/version-24.x/Configuration.md

@@ -1064,6 +1064,7 @@ Example:
 Sort test path alphabetically.
 
 ```js
+// testSequencer.js
 const Sequencer = require('@jest/test-sequencer').default;
 
 class CustomSequencer extends Sequencer {
@@ -1078,6 +1079,14 @@ class CustomSequencer extends Sequencer {
 module.exports = CustomSequencer;
 ```
 
+Use it in your Jest config file like this:
+
+```json
+{
+  "testSequencer": "path/to/testSequencer.js"
+}
+```
+
 ### `testURL` [string]
 
 Default: `http://localhost`

website/versioned_docs/version-25.5/Configuration.md

@@ -1086,6 +1086,7 @@ Example:
 Sort test path alphabetically.
 
 ```js
+// testSequencer.js
 const Sequencer = require('@jest/test-sequencer').default;
 
 class CustomSequencer extends Sequencer {
@@ -1100,6 +1101,14 @@ class CustomSequencer extends Sequencer {
 module.exports = CustomSequencer;
 ```
 
+Use it in your Jest config file like this:
+
+```json
+{
+  "testSequencer": "path/to/testSequencer.js"
+}
+```
+
 ### `testTimeout` [number]
 
 Default: `5000`