Use the current stack version in the landing page

Author: cotti

src/Elastic.Markdown/Layout/_LandingPage.cshtml

@@ -10,7 +10,7 @@
 		<div class="container mx-auto pt-16 pb-10 grid md:grid-cols-2 items-center gap-6">
 			<div>
 				<h1 class="text-4xl font-bold font-sans text-black">Elastic Docs</h1>
-				<p class="mt-4">Welcome to the docs that cover all changes in <span class="whitespace-nowrap">Elastic Stack 9.0.0</span> and later, including <span class="whitespace-nowrap">Elastic Stack 9.1.0</span> and <span class="whitespace-nowrap">Elastic Cloud Serverless</span>.
+				<p class="mt-4">Welcome to the docs that cover all changes in <span class="whitespace-nowrap">Elastic Stack 9.0.0</span> and later, including <span class="whitespace-nowrap">Elastic Stack @Model.CurrentVersion</span> and <span class="whitespace-nowrap">Elastic Cloud Serverless</span>.
 					For easy reference, changes in 9.1.0 are marked inline. For details, check <a href="https://www.elastic.co/docs/get-started/versioning-availability" class="link">Understanding versioning and availability.</a></p>
 				<div class="flex md:inline-flex gap-3 mt-6">
 					<a href="@Model.Link("/get-started/")" class="grow select-none cursor-pointer text-white text-nowrap bg-blue-elastic hover:bg-blue-elastic-110 focus:ring-4 focus:ring-blue-elastic-50 font-semibold font-sans rounded-sm px-6 py-2 focus:outline-none h-10 flex items-center justify-center">

src/Elastic.Markdown/Page/Index.cshtml

@@ -37,7 +37,7 @@
 		StaticFileContentHashProvider = Model.StaticFileContentHashProvider,
 		ReportIssueUrl = Model.ReportIssueUrl,
 		LegacyPages = Model.LegacyPages,
-		CurrentVersion = Model.CurrentVersion,
+		CurrentVersion = Model.CurrentDocument.YamlFrontMatter?.Layout == MarkdownPageLayout.LandingPage ? Model.VersionsConfig.VersioningSystems[0].Current : Model.CurrentVersion,
 		AllVersionsUrl = Model.AllVersionsUrl,
 		VersionDropdownSerializedModel = JsonSerializer.Serialize(Model.VersionDropdownItems,
 			ViewModelSerializerContext.Default.VersionDrownDownItemViewModelArray),