hugolib: Restore taxonomy term path separation

Fixes #5513

hugolib/taxonomy_test.go

@@ -243,3 +243,44 @@ subcats:
 	th.assertFileContent(pathFunc("public/empties/index.html"), "Terms List", "Empties")
 
 }
+
+// https://github.com/gohugoio/hugo/issues/5513
+func TestTaxonomyPathSeparation(t *testing.T) {
+	t.Parallel()
+
+	config := `
+baseURL = "https://example.com"
+
+[taxonomies]
+"news/tag" = "news/tags"
+"news/category" = "news/categories"
+`
+
+	pageContent := `
++++
+title = "foo"
+"news/categories" = ["a", "b", "c"]
++++
+
+Content.
+
+
+`
+
+	b := newTestSitesBuilder(t)
+	b.WithConfigFile("toml", config)
+	b.WithContent("page.md", pageContent)
+	b.WithContent("news/categories/b/_index.md", `
+---
+title: "This is B"
+---
+
+`)
+
+	b.CreateSites().Build(BuildCfg{})
+
+	b.AssertFileContent("public/news/categories/index.html", "Taxonomy Term Page 1|News/Categories|Hello|https://example.com/news/categories/|")
+	b.AssertFileContent("public/news/categories/a/index.html", "Taxonomy List Page 1|A|Hello|https://example.com/news/categories/a/|")
+	b.AssertFileContent("public/news/categories/b/index.html", "Taxonomy List Page 1|This is B|Hello|https://example.com/news/categories/b/|")
+
+}