Add Page.RenderShortcodes

A layouts/shortcodes/include.html shortcode may look like this:

```html
{{ $p := site.GetPage (.Get 0) }}
{{ $p.RenderShortcodes }}
```

Fixes #7297

hugolib/rendershortcodes_test.go

@@ -0,0 +1,232 @@
+// Copyright 2023 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package hugolib
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestRenderShortcodesBasic(t *testing.T) {
+	t.Parallel()
+
+	files := `
+-- hugo.toml --
+disableKinds = ["home", "taxonomy", "term"]
+-- content/p1.md --
+---
+title: "p1"
+---
+## p1-h1
+{{% include "p2" %}}
+-- content/p2.md --
+---
+title: "p2"
+---
+### p2-h1
+{{< withhtml >}}
+### p2-h2
+{{% withmarkdown %}}
+### p2-h3
+{{% include "p3" %}}
+-- content/p3.md --
+---
+title: "p3"
+---
+### p3-h1
+{{< withhtml >}}
+### p3-h2
+{{% withmarkdown %}}
+{{< level3 >}}
+-- layouts/shortcodes/include.html --
+{{ $p := site.GetPage (.Get 0) }}
+{{ $p.RenderShortcodes }}
+-- layouts/shortcodes/withhtml.html --
+<div>{{ .Page.Title }} withhtml</div>
+-- layouts/shortcodes/withmarkdown.html --
+#### {{ .Page.Title }} withmarkdown
+-- layouts/shortcodes/level3.html --
+Level 3: {{ .Page.Title }}
+-- layouts/_default/single.html --
+Fragments: {{ .Fragments.Identifiers }}|
+HasShortcode Level 1: {{ .HasShortcode "include" }}|
+HasShortcode Level 2: {{ .HasShortcode "withmarkdown" }}|
+HasShortcode Level 3: {{ .HasShortcode "level3" }}|
+HasSHortcode not found: {{ .HasShortcode "notfound" }}|
+Content: {{ .Content }}|
+`
+
+	b := NewIntegrationTestBuilder(
+		IntegrationTestConfig{
+			T:           t,
+			TxtarString: files,
+		},
+	).Build()
+
+	b.AssertFileContent("public/p1/index.html",
+		"Fragments: [p1-h1 p2-h1 p2-h2 p2-h3 p2-withmarkdown p3-h1 p3-h2 p3-withmarkdown]|",
+		"HasShortcode Level 1: true|",
+		"HasShortcode Level 2: true|",
+		"HasShortcode Level 3: true|",
+		"HasSHortcode not found: false|",
+	)
+
+	// TODO1 more assertions.
+
+}
+
+func TestRenderShortcodesNestedMultipleOutputFormatTemplates(t *testing.T) {
+	t.Parallel()
+
+	files := `
+-- hugo.toml --
+disableKinds = ["home", "taxonomy", "term", "section", "rss", "sitemap", "robotsTXT", "404"]
+[outputs]
+page = ["html", "json"]
+-- content/p1.md --
+---
+title: "p1"
+---
+## p1-h1
+{{% include "p2" %}}
+-- content/p2.md --
+---
+title: "p2"
+---
+### p2-h1
+{{% myshort %}}
+-- layouts/shortcodes/include.html --
+{{ $p := site.GetPage (.Get 0) }}
+{{ $p.RenderShortcodes }}
+-- layouts/shortcodes/myshort.html --
+Myshort HTML.
+-- layouts/shortcodes/myshort.json --
+Myshort JSON.
+-- layouts/_default/single.html --
+HTML: {{ .Content }}
+-- layouts/_default/single.json --
+JSON: {{ .Content }}
+
+
+`
+
+	b := NewIntegrationTestBuilder(
+		IntegrationTestConfig{
+			T:           t,
+			TxtarString: files,
+		},
+	).Build()
+
+	b.AssertFileContent("public/p1/index.html", "Myshort HTML")
+	b.AssertFileContent("public/p1/index.json", "Myshort JSON")
+
+}
+
+func TestRenderShortcodesEditNested(t *testing.T) {
+	t.Parallel()
+
+	files := `
+-- hugo.toml --
+disableLiveReload = true
+disableKinds = ["home", "taxonomy", "term", "section", "rss", "sitemap", "robotsTXT", "404"]
+-- content/p1.md --
+---
+title: "p1"
+---
+## p1-h1
+{{% include "p2" %}}
+-- content/p2.md --
+---
+title: "p2"
+---
+### p2-h1
+{{% myshort %}}
+-- layouts/shortcodes/include.html --
+{{ $p := site.GetPage (.Get 0) }}
+{{ $p.RenderShortcodes }}
+-- layouts/shortcodes/myshort.html --
+Myshort Original.
+-- layouts/_default/single.html --
+ {{ .Content }}
+
+
+
+`
+
+	b := NewIntegrationTestBuilder(
+		IntegrationTestConfig{
+			T:           t,
+			TxtarString: files,
+			Running:     true,
+		},
+	).Build()
+
+	b.AssertFileContent("public/p1/index.html", "Myshort Original.")
+
+	b.EditFileReplace("layouts/shortcodes/myshort.html", func(s string) string {
+		return "Myshort Edited."
+	})
+	b.Build()
+	b.AssertFileContent("public/p1/index.html", "Myshort Edited.")
+
+}
+
+func TestRenderShortcodesEditIncludedPage(t *testing.T) {
+	t.Parallel()
+
+	files := `
+-- hugo.toml --
+disableLiveReload = true
+disableKinds = ["home", "taxonomy", "term", "section", "rss", "sitemap", "robotsTXT", "404"]
+-- content/p1.md --
+---
+title: "p1"
+---
+## p1-h1
+{{% include "p2" %}}
+-- content/p2.md --
+---
+title: "p2"
+---
+### Original
+{{% myshort %}}
+-- layouts/shortcodes/include.html --
+{{ $p := site.GetPage (.Get 0) }}
+{{ $p.RenderShortcodes }}
+-- layouts/shortcodes/myshort.html --
+Myshort Original.
+-- layouts/_default/single.html --
+ {{ .Content }}
+
+
+
+`
+
+	b := NewIntegrationTestBuilder(
+		IntegrationTestConfig{
+			T:           t,
+			TxtarString: files,
+			Running:     true,
+		},
+	).Build()
+
+	b.AssertFileContent("public/p1/index.html", "Original")
+
+	b.EditFileReplace("content/p2.md", func(s string) string {
+		return strings.Replace(s, "Original", "Edited", 1)
+	})
+	b.Build()
+	b.AssertFileContent("public/p1/index.html", "Edited")
+
+}