Add Caching to introduction and readme (#3031)

- Fix rate limiting guide with correct example

### Description of change

##### Checklist

- [ ] Tested in playground or other setup
- [ ] Screenshot (Grafana) from playground added to PR for 15+ minute
run
- [x] Documentation is changed or added
- [ ] Tests and/or benchmarks are included
- [ ] Breaking changes


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **Documentation**
- Updated the README to include information on new caching features for
performance improvement and cost reduction.
- Revised the developer guide on per-user rate limiting to reflect code
examples in TypeScript instead of Python.
- Added a section in the introduction about the benefits of caching
within the application.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

README.md

@@ -80,6 +80,9 @@ cloud application:
   Aperture aligns resource distribution with business value and urgency of
   requests. Workload prioritization applies to API Quota Management and Adaptive
   Queuing use cases.
+- 💾 [**Caching**]: Boost application performance and reduce costs by caching
+  costly operations, preventing duplicate requests to pay-per-use services, and
+  easing the load on constrained services.
 
 ## 🏗️ Architecture
 

docs/content/guides/per-user-rate-limiting.md

@@ -65,7 +65,7 @@ The first step to use Aperture SDK is to import and set up Aperture Client:
 <TabItem value="Typescript">
 ```
 
-<CodeSnippet lang="py" snippetName="clientConstructor" />
+<CodeSnippet lang="ts" snippetName="clientConstructor" />
 
 ```mdx-code-block
   </TabItem>

docs/content/introduction.md

@@ -74,6 +74,9 @@ To sign-up to Aperture Cloud, [click here][sign-up].
   Aperture aligns resource distribution with business value and urgency of
   requests. Workload prioritization applies to API Quota Management and Adaptive
   Queuing use cases.
+- 💾 [**Caching**]: Boost application performance and reduce costs by caching
+  costly operations, preventing duplicate requests to pay-per-use services, and
+  easing the load on constrained services.
 
 ## ✨ Get started {#get-started}