guides: display links to openapi complete guide

Adds an entry in the main navbar and a highlight banner in the main
guides page.

src/_components/shared/highlight_banner.rb

@@ -1,7 +1,6 @@
 class Shared::HighlightBanner < Bridgetown::Component
-  def initialize(title:, description: "", image: "", link_url: "", link_label: "", link_icon: "")
+  def initialize(title:, image: "", link_url: "", link_label: "", link_icon: "")
     @title = title
-    @description = description
     @image = image
     @link_url = link_url
     @link_label = link_label

src/_data/navbar.yml

@@ -2,6 +2,7 @@ left_links:
   - {title: "Documentation", link: "/help"}
   - {title: "Product Updates", link: "/product-updates"}
   - {title: "Guides", link: "/guides"}
+  - {title: "OpenAPI", link: "/guides/openapi/specification/v3.1/introduction/what-is-openapi"}
 right_links:
   - {title: "API Reference", link: "https://developers.bump.sh"}
   - {title: "Bump.sh", link: "https://bump.sh"}

src/_pages/guides.md

@@ -3,3 +3,13 @@ layout: guides
 title: Guides
 page_class: guides
 ---
+
+<%= render Shared::HighlightBanner.new(
+  title: "OpenAPI: The Complete Guide",
+  image: "images/logos/openapi.svg",
+  link_url: "/guides/openapi/specification/v3.1/introduction/what-is-openapi",
+  link_label: "Discover the guide",
+  link_icon: "images/icons/documentation.svg") do %>
+    <p>This guide is designed to give you a step-by-step overview of OpenAPI.
+Discover the reasons behind its creation, its capabilities and how to make a good OpenAPI API from scratch, from design to maintenance.</p>
+<% end %>