update performance page to expected navigation and fix nav issues in the page (#1774)

Author: PeloWriter

__tests__/__snapshots__/documentation.js.snap

@@ -281,7 +281,7 @@ Array [
   "performance/discover/index.html",
   "performance/discover/query-builder/index.html",
   "performance/distributed-tracing/index.html",
-  "performance/index.html",
+  "performance/getting-started/index.html",
   "performance/performance-homepage/index.html",
   "performance/performance-metrics/index.html",
   "platforms/android/index.html",

src/collections/_documentation/performance/index.md renamed to src/collections/_documentation/performance/getting-started.md

@@ -1,5 +1,5 @@
 ---
-title: Performance Monitoring
+title: Getting Started
 sidebar_order: 0
 ---
 
@@ -12,6 +12,8 @@ Learn more about performance monitoring in:
 - [Metrics]({% link _documentation/performance/performance-metrics.md %}): provides insight into user experience of your application based on custom thresholds
 - [Discover]({% link _documentation/performance/discover/index.md %}): view data across environments with pre-built queries. Customers subscribed to the Team or Business plan can use Discover to view comprehensive information sent to Sentry.
 
+## Install
+
 {% include components/platform_content.html content_dir='getting-started' %}
 
 ## Navigating Performance Data

src/collections/_documentation/performance/getting-started/javascript.md

@@ -1,6 +1,4 @@
-## Getting Started with Performance for JavaScript
-
-To get started with performance monitoring, first install the `@sentry/apm` package:
+To get started with performance monitoring using Sentry's JavaScript SDK, first install the `@sentry/apm` package:
 
 ```bash
 npm install --save @sentry/apm

src/collections/_documentation/performance/getting-started/python.md

@@ -1,4 +1,4 @@
-## Getting Started with Performance for Python
+To get started with performance monitoring using Sentry's Python SDK, first install the `@sentry/apm` package:
 
 ```
 import sentry_sdk

src/collections/_documentation/performance/performance-homepage.md

@@ -1,6 +1,6 @@
 ---
 title: 'Performance Homepage'
-sidebar_order: 1
+sidebar_order: 2
 ---
 {% capture __alert_content -%}
 Sentry's Performance features are currently in beta. For more details about access to these features, feel free to reach out at [[email protected]](mailto:[email protected]).

src/collections/_documentation/performance/performance-metrics.md

@@ -1,6 +1,6 @@
 ---
 title: 'Performance Metrics'
-sidebar_order: 0
+sidebar_order: 1
 ---
 {% capture __alert_content -%}
 Sentry's Performance features are currently in beta. For more details about access to these features, feel free to reach out at [[email protected]](mailto:[email protected]).