Make it compatible with Hugo 0.55 (#13680)

This commit adds two backwards compatible changes to prepare for the next Hugo version, most notable:

* All the `File` methods on `Page` has been deprecated and will give a warning in the next Hugo version. Adjust this by changing `.Dir` to ´.File.Dir` and similar.
* Version the capture shortcode to use the old behaviour for markdown rendering of shortcode inner content.

layouts/partials/docs/top-menu.html

@@ -4,7 +4,7 @@
 {{ $menuSections := (where $docs.Sections ".Params.main_menu" true) }}
 {{ range $menuSections }}
 {{ if $p.IsDescendant . }}
-<h1>{{ if not (strings.Contains .Dir "home")}}{{ .Params.bigheader | default .Title }}{{ end }}</h1>
+<h1>{{ if not (strings.Contains .Path "home")}}{{ .Params.bigheader | default .Title }}{{ end }}</h1>
 <h5>{{ .Params.abstract }}</h5>
 {{ end }}
 {{ end }}

layouts/partials/git-info.html

@@ -19,7 +19,7 @@
     {{ end }}
     {{ end }}
     {{ if not .Params.noedit }}
-    <a href="https://github.com/kubernetes/website/edit/master/content/{{ site.Language.Lang }}/{{ .File.Path }}" class="button issue">{{ T "main_edit_this_page" }}</a>
+    {{ if .File }}<a href="https://github.com/kubernetes/website/edit/master/content/{{ site.Language.Lang }}/{{ .File.Path }}" class="button issue">{{ T "main_edit_this_page" }}</a>{{ end }}
     {{ end }}
   </div>
   {{ if and (not .Params.showcommit) $.GitInfo }}

layouts/partials/templates/blocks.html

@@ -1,10 +1,10 @@
 {{ .ctx.Scratch.Set "sections" slice }}
 <ul id="markdown-toc">
 {{ range .ctx.Scratch.Get "blocks" }}
-{{ if .content }}
-{{ $.ctx.Scratch.Set "section" .content }}
-{{ else}}
+{{ if .block }}
 {{ $.ctx.Scratch.Set "section" (partial "templates/block" .) }}
+{{ else}}
+{{ $.ctx.Scratch.Set "section" .content }}
 {{ end }}
 {{ $section := $.ctx.Scratch.Get "section" }}
 {{ $headers := findRE "<h2.*?>(.|\n)*?</h2>" $section }}