fix media description render for orgmode (#26895)

- In org mode you can specify an description for media via the following
syntax `[[description][media link]]`. The description is then used as
title or alt.
- This patch fixes the rendering of the description by seperating the
description and non-description cases and using `org.String()`.
- Added unit tests.
- Inspired by
6eb20dbda9/org/html_writer.go (L406-L427)
- Resolves https://codeberg.org/Codeberg/Community/issues/848

(cherry picked from commit 8b8aab8311)

Co-authored-by: Gusted <postmaster@gusted.xyz>

modules/markup/orgmode/orgmode_test.go

@@ -42,7 +42,7 @@ func TestRender_StandardLinks(t *testing.T) {
 		"<p><a href=\""+lnk+"\" title=\"WikiPage\">WikiPage</a></p>")
 }
 
-func TestRender_Images(t *testing.T) {
+func TestRender_Media(t *testing.T) {
 	setting.AppURL = AppURL
 	setting.AppSubURL = AppSubURL
 
@@ -60,6 +60,18 @@ func TestRender_Images(t *testing.T) {
 
 	test("[[file:"+url+"]]",
 		"<p><img src=\""+result+"\" alt=\""+result+"\" title=\""+result+"\" /></p>")
+
+	// With description.
+	test("[[https://example.com][https://example.com/example.svg]]",
+		`<p><a href="https://example.com"><img src="https://example.com/example.svg" alt="https://example.com/example.svg" /></a></p>`)
+	test("[[https://example.com][https://example.com/example.mp4]]",
+		`<p><a href="https://example.com"><video src="https://example.com/example.mp4" title="https://example.com/example.mp4"></video></a></p>`)
+
+	// Without description.
+	test("[[https://example.com/example.svg]]",
+		`<p><img src="https://example.com/example.svg" alt="https://example.com/example.svg" title="https://example.com/example.svg" /></p>`)
+	test("[[https://example.com/example.mp4]]",
+		`<p><video src="https://example.com/example.mp4" title="https://example.com/example.mp4">https://example.com/example.mp4</video></p>`)
 }
 
 func TestRender_Source(t *testing.T) {