Add a public initializer to RenderContentMetadata

Sources/SwiftDocC/Model/Rendering/Content/RenderContentMetadata.swift

@@ -20,6 +20,15 @@ public struct RenderContentMetadata: Equatable, Codable {
     public var abstract: [RenderInlineContent]?
     /// An optional identifier for the device frame that should wrap this element.
     public var deviceFrame: String?
+
+    /// Declare a public initializer, to allow clients linking to Swift DocC to
+    /// create RenderContentMetadata values.
+    public init(anchor: String? = nil, title: String? = nil, abstract: [RenderInlineContent]? = nil, deviceFrame: String? = nil) {
+        self.anchor = anchor
+        self.title = title
+        self.abstract = abstract
+        self.deviceFrame = deviceFrame
+    }
 }
 
 extension RenderContentMetadata {

Tests/SwiftDocCTests/Model/RenderContentMetadataInitializerTests.swift

@@ -0,0 +1,31 @@
+/*
+ This source file is part of the Swift.org open source project
+
+ Copyright (c) 2025 Apple Inc. and the Swift project authors
+ Licensed under Apache License v2.0 with Runtime Library Exception
+
+ See https://swift.org/LICENSE.txt for license information
+ See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+*/
+
+// Import SwiftDocC without the @testable annotation, so we can test there
+// is a public initializer for RenderContentMetadata.
+import SwiftDocC
+import XCTest
+
+class RenderContentMetadataInitializerTests: XCTestCase {
+    func testMetadataPublicInitializer() throws {
+        let metadata = RenderContentMetadata(
+            anchor: "anchor",
+            title: "title",
+            abstract: [],
+            deviceFrame: "device frame"
+        )
+
+        XCTAssertNotNil(metadata)
+        XCTAssertEqual("anchor", metadata.anchor)
+        XCTAssertEqual("title", metadata.title)
+        XCTAssertEqual([], metadata.abstract)
+        XCTAssertEqual("device frame", metadata.deviceFrame)
+    }
+}