fix: test for page context in download asset

Author: markdumay

layouts/_partials/assets/download.html

@@ -19,15 +19,21 @@
     {{ $error = $args.err }}
 {{ end }}
 
+{{ $download := "" }}
 {{ if not $error }}
-    {{/* Initialize local arguments */}}
-    {{- $title := $args.title -}}
-    {{- $download := partial "utilities/GetTargetPath.html" (dict "path" $args.download "page" page) -}}
+    {{- $download = partial "utilities/GetTargetPath.html" (dict "path" $args.download "page" page) -}}
     {{- if and $download (not (fileExists (path.Join "static" $download))) -}}
-        {{- errorf "Cannot find download file for page '%s': %s" page.File.Path $download -}}
+        {{ if page }}
+            {{- errorf "Cannot find download file for page '%s': %s" page.File.Path $download -}}
+        {{ else }}
+            {{- errorf "Cannot find download file: %s" $download -}}
+        {{ end }}
         {{- $error = true }}
     {{- end -}}
+{{- end -}}
 
+{{ if not $error }}
+    {{- $title := $args.title -}}
     {{ if not $title }}
         {{ if not $args.minimal }}{{ $title = (T "download" ) }}{{ end }}
         {{ $lang := strings.TrimPrefix "." (path.Ext (path.BaseName $download)) }}