Do not emit See Also sections for variants that have no See Also topics

When an Objective-C symbol has no See Also topics, or when it has empty
See Also topic groups, dont' emit a See Also section for it, rather
than defaulting to the Swift's variant's See Also topics.

Author: franklinsch

Sources/SwiftDocC/Model/Rendering/RenderNodeTranslator.swift

@@ -1350,22 +1350,20 @@ public struct RenderNodeTranslator: SemanticVisitor {
                 bundle: bundle,
                 renderContext: renderContext,
                 renderer: contentRenderer
-            ) {
+            ), !seeAlso.references.isEmpty {
                 contentCompiler.collectedTopicReferences.append(contentsOf: seeAlso.references)
-                seeAlsoSections.append(TaskGroupRenderSection(
-                    title: seeAlso.title,
-                    abstract: nil,
-                    discussion: nil,
-                    identifiers: seeAlso.references.map { $0.absoluteString },
-                    generated: true
-                ))
+                seeAlsoSections.append(
+                    TaskGroupRenderSection(
+                        title: seeAlso.title,
+                        abstract: nil,
+                        discussion: nil,
+                        identifiers: seeAlso.references.map { $0.absoluteString },
+                        generated: true
+                    )
+                )
             }
 
-            if seeAlsoSections.isEmpty {
-                return nil
-            } else {
-                return seeAlsoSections
-            }
+            return seeAlsoSections
         } ?? .init(defaultValue: [])
 
         node.deprecationSummaryVariants = VariantCollection<[RenderBlockContent]?>(

Tests/SwiftDocCTests/Rendering/RenderNodeTranslatorSymbolVariantsTests.swift

@@ -990,6 +990,30 @@ class RenderNodeTranslatorSymbolVariantsTests: XCTestCase {
         )
     }
 
+    func testDoesNotEmitObjectiveCSeeAlsoIfEmpty() throws {
+        func makeSeeAlsoSection(destination: String) -> SeeAlsoSection {
+            SeeAlsoSection(content: [
+                UnorderedList(
+                    ListItem(Paragraph(Link(destination: destination)))
+                )
+            ])
+        }
+        
+        try assertMultiVariantSymbol(
+            configureSymbol: { symbol in
+                symbol.seeAlsoVariants[.swift] = makeSeeAlsoSection(
+                    destination: "doc://org.swift.docc.example/documentation/MyKit/MyProtocol"
+                )
+            },
+            assertOriginalRenderNode: { renderNode in
+                XCTAssertEqual(renderNode.seeAlsoSections.count, 2)
+            },
+            assertAfterApplyingVariant: { renderNode in
+                XCTAssert(renderNode.seeAlsoSections.isEmpty)
+            }
+        )
+    }
+    
     func testDeprecationSummaryVariants() throws {
         try assertMultiVariantSymbol(
             configureSymbol: { symbol in