Only set the docsearch facet based on the URL version

Together with the Algolia ignoreCanonicalTo setting set to true, this might allow to get hits with the version the user is on instead of the alias

Author: Simran-B

site/themes/arangodb-docs-theme/layouts/partials/meta.html

@@ -13,10 +13,10 @@
 {{- with .Site.Params.author }}
 <meta name="author" content="{{ . }}">
 {{- end }}
-{{- $versionShort := .Page.Store.Get "versionShort" }}
-{{- $versionAlias := .Page.Store.Get "alias" }}
-{{- if $versionShort -}}
-  <meta name="docsearch:version" content="{{ $versionShort }}{{ if ne $versionShort $versionAlias }},{{ $versionAlias }}{{ end }}">
+{{- $splitPath := split .Path "/" }}
+{{- if and (hasPrefix .Path "/arangodb/") (ge ($splitPath | len) 3) }}
+  {{- $coreVersion := index $splitPath 2 }}
+  <meta name="docsearch:version" content="{{ $coreVersion }}">
 {{- else }}
   {{- $shortVersions := slice }}
   {{- $versions := index site.Data.versions "/arangodb/" }}