Update documentation for style consistency (#2256)

This commit updates most of the documentation set to adhere to some
contemporary documentation style standards:

- Sentence case for titles and headings
- Initial headings for how-to guides as "Overview" and 
"Before you begin"
- Moving any frontmatter descriptions to the body of text
- Removing unnecessary frontmatter data altogether
- Removing unnecessary custom style tag (Incorporated 
into the theme by default)

It also collapses a few single document directories 
(Adding an unnecessary "hop" for users) and re-orders some sections.

Author: ADubhlaoich

site/config/api/pkg.tpl

@@ -1,11 +1,14 @@
 {{ define "packages" }}
 ---
-title: "API Reference"
-description: "NGINX Gateway API Reference"
+title: "API reference"
 weight: 100
 toc: false
 ---
 
+## Overview
+
+NGINX Gateway API Reference
+
 {{ with .packages}}
 <p>Packages:</p>
 <ul>

site/content/how-to/_index.md

@@ -1,9 +1,4 @@
 ---
-title: "How-To Guides"
-description:
+title: "How-to guides"
 weight: 300
-linkTitle: "Guides"
-menu:
-  docs:
-    parent: NGINX Gateway Fabric
 ---

site/content/how-to/configuration/_index.md

@@ -1,11 +1,12 @@
 ---
-title: "Control Plane Configuration"
-description: "Learn how to dynamically update the Gateway Fabric control plane configuration."
-weight: 100
+title: "Control plane configuration"
+weight: 300
 toc: true
 docs: "DOCS-1416"
 ---
 
+Learn how to dynamically update the Gateway Fabric control plane configuration.
+
 ## Overview
 
 NGINX Gateway Fabric can dynamically update the control plane configuration without restarting. The control plane configuration is stored in the NginxGateway custom resource, created during the installation of NGINX Gateway Fabric.

site/content/how-to/configuration/control-plane-configuration.md renamed to site/content/how-to/control-plane-configuration.md

@@ -1,9 +1,4 @@
 ---
-title: "Monitoring and Troubleshooting"
-description:
-weight: 400
-linkTitle: "Monitoring and Troubleshooting"
-menu:
-  docs:
-    parent: How-To Guides
+title: "Monitoring and troubleshooting"
+weight: 200
 ---

site/content/how-to/maintenance/_index.md

@@ -1,12 +1,11 @@
 ---
-title: "NGINX Plus Dashboard"
-description: "Learn how to view the NGINX Plus dashboard to see real-time metrics."
+title: "NGINX Plus dashboard"
 weight: 300
 toc: true
 docs: "DOCS-1417"
 ---
 
-{{<custom-styles>}}
+Learn how to view the NGINX Plus dashboard to see real-time metrics.
 
 ## Overview
 

site/content/how-to/monitoring/_index.md

@@ -1,16 +1,14 @@
 ---
-title: "Prometheus Metrics"
-description: "This document describes how to monitor NGINX Gateway Fabric using Prometheus and Grafana. It explains installation and configuration, as well as what metrics are available."
+title: "Prometheus metrics"
 weight: 100
 toc: true
 docs: "DOCS-1418"
 ---
 
-{{<custom-styles>}}
+This document describes how to monitor NGINX Gateway Fabric using Prometheus and Grafana. It explains installation and configuration, as well as what metrics are available.
 
 ## Overview
 
-
 NGINX Gateway Fabric metrics are displayed in [Prometheus](https://prometheus.io/) format. These metrics are served through a metrics server orchestrated by the controller-runtime package on HTTP port `9113`. When installed, Prometheus automatically scrapes this port and collects metrics. [Grafana](https://grafana.com/) can be used for rich visualization of these metrics.
 
 {{<call-out "important" "Security note for metrics">}}
@@ -98,7 +96,7 @@ Provided by the [controller-runtime](https://github.com/kubernetes-sigs/controll
 - Go runtime metrics such as the number of Go routines, garbage collection duration, and Go version.
 - Controller-specific metrics, including reconciliation errors per controller, length of the reconcile queue, and reconciliation latency.
 
-## How to change the default metrics configuration
+## Change the default metrics configuration
 
 You can configure monitoring metrics for NGINX Gateway Fabric using Helm or Manifests.
 

site/content/how-to/monitoring/dashboard.md

@@ -17,7 +17,7 @@ This guide explains how to enable tracing on HTTPRoutes using NGINX Gateway Fabr
 Tracing cannot be enabled for [HTTPRoute matches](https://gateway-api.sigs.k8s.io/reference/spec/#gateway.networking.k8s.io/v1.HTTPRouteMatch) with `headers`, `params`, or `method` matchers defined. It will be added in a future release.
 {{< /important >}}
 
-## Install the Collectors
+## Install the collectors
 
 The first step is to install the collectors. NGINX Gateway Fabric will be configured to export to the OpenTelemetry Collector, which is configured to export to Jaeger. This model allows the visualization collector (Jaeger) to be swapped with something else, or to add more collectors without needing to reconfigure NGINX Gateway Fabric. It is also possible to configure NGINX Gateway Fabric to export directly to Jaeger.
 
@@ -333,7 +333,7 @@ Select a trace to view the attributes.
 
 The trace includes the attribute from the global NginxProxy resource as well as the attribute from the ObservabilityPolicy.
 
-## Further Reading
+## Further reading
 
 - [Custom policies]({{< relref "overview/custom-policies.md" >}}): learn about how NGINX Gateway Fabric custom policies work.
 - [API reference]({{< relref "reference/api.md" >}}): all configuration fields for the policies mentioned in this guide

site/content/how-to/monitoring/prometheus.md

@@ -5,11 +5,8 @@ toc: true
 docs: "DOCS-1419"
 ---
 
-{{< custom-styles >}}
-
 This topic describes possible issues when using NGINX Gateway Fabric and general troubleshooting techniques. When possible, suggested workarounds are provided.
 
-
 ### General troubleshooting
 
 When investigating a problem or requesting help, there are important data points that can be collected to help understand what issues may exist.