Shorter nav names for tutorials while maintaining SEO titles (#6028)

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## About the changes
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Let's update our tutorial titles in the left navigation menu so it's
shorter and simpler.
This will _not_ change the metadata and doc titles when you click on
them. Only the label in the nav.

BEFORE
![Screenshot 2024-01-24 at 9 52
17 AM](https://github.com/Unleash/unleash/assets/22972707/283b22c5-c317-4140-8478-67965d004ef1)

AFTER
![Screenshot 2024-01-24 at 9 47
37 AM](https://github.com/Unleash/unleash/assets/22972707/04c58f24-1e1f-4f83-b1ff-1eeba670a092)


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website/docs/feature-flag-tutorials/react/examples.md

@@ -3,8 +3,6 @@ title: React Feature Flag Examples
 slug: /feature-flag-tutorials/react/examples
 ---
 
-# React Feature Flag Examples
-
 In our [React tutorial](/feature-flag-tutorials/react), we implemented a simple on/off feature flag that could be turned on and off. In the real world, many feature flag use cases have more nuance than this. This document will walk you through some common examples of using feature flags in React with some of those more advanced use cases in mind. 
 
 Applications evolve, and teams must manage all aspects of this evolution, including the flags used to control the application. We built multiple features into Unleash to address the complexities of releasing code and managing feature flags along the way:

website/sidebars.js

@@ -94,26 +94,38 @@ module.exports = {
             items: [
                 {
                     type: 'category',
-                    label: 'How to Implement Feature Feature Flags in React',
+                    label: 'React',
                     link: {
                         type: 'doc',
                         id: 'feature-flag-tutorials/react/implementing-feature-flags',
                     },
                     items: [
-                        'feature-flag-tutorials/react/examples',
+                        {
+                            type: 'doc',
+                            label: 'Examples',
+                            id: 'feature-flag-tutorials/react/examples',
+                        },
                     ],
                 },
                 {
                     type: 'category',
-                    label: 'How to Implement Feature Flags in Python',
+                    label: 'Python',
                     link: {
                         type: 'doc',
                         id: 'feature-flag-tutorials/python/implementing-feature-flags',
                     },
                     items: [],
                 },
-                'feature-flag-tutorials/flutter/a-b-testing',
-                'feature-flag-tutorials/nextjs/implementing-feature-flags',
+                {
+                    type: 'doc',
+                    label: 'Flutter',
+                    id: 'feature-flag-tutorials/flutter/a-b-testing',
+                },
+                {
+                    type: 'doc',
+                    label: 'Next.js',
+                    id: 'feature-flag-tutorials/nextjs/implementing-feature-flags',
+                },
             ],
         },
         {