Widget page: filter by tag/category breaks down if blank space

[Bertbk]

Problem

The filter by tag (or category) of the pages widget does not work if the tag (or category) contains a blank space. For example:

# content/talk/mytalk.index.md 
tags = ["Great tag"]

# content/home/talks.md 
[content.filters]
    tag = "Great tag"

This is due to the fact that the query is made on an url in layout/widgets/partials/pages.html:

{{ if $st.Params.content.filters.category }}
  {{ $archive_page = site.GetPage (printf "categories/%s" $st.Params.content.filters.category) }}
  {{ $query = $query | intersect $archive_page.Pages }}
{{ end }}

Hugo will look at webiste.com/tags/Great tag instead of its url version webiste.com/tags/great-tag.

Possible fix

I suggest to add urlize (3 times: tags, categories, and publication_types):

{{ if $st.Params.content.filters.category }}
  {{ $archive_page = site.GetPage (urlize (printf "categories/%s" $st.Params.content.filters.category)) }}
  {{ $query = $query | intersect $archive_page.Pages }}
{{ end }}

Enhancement?

By the way, it might better to allow multiple tags (or categories) as a filter instead of only one?