don't emit both requirementOf and optionalRequirementOf for the same relationship (#76983)

rdar://83519993

Author: QuietMisdreavus

lib/SymbolGraphGen/SymbolGraph.cpp

@@ -465,7 +465,8 @@ void
 SymbolGraph::recordRequirementRelationships(Symbol S) {
   const auto VD = S.getSymbolDecl();
   if (const auto *Protocol = dyn_cast<ProtocolDecl>(VD->getDeclContext())) {
-    if (VD->isProtocolRequirement()) {
+    if (VD->isProtocolRequirement() &&
+        !VD->getAttrs().hasAttribute<OptionalAttr>()) {
       recordEdge(Symbol(this, VD, nullptr),
                  Symbol(this, Protocol, nullptr),
                  RelationshipKind::RequirementOf());

test/SymbolGraph/Relationships/OptionalRequirementOf.swift

@@ -9,11 +9,11 @@
 // RUN: %FileCheck %s --input-file %t/OptionalRequirementOf.symbols.json
 
 // ObjCProto.objcReq -> ObjCProto
-// CHECK-DAG: "kind": "requirementOf",{{[[:space:]]*}}"source": "c:@M@OptionalRequirementOf@objc(pl)SwiftProto(im)swiftReq",{{[[:space:]]*}}"target": "c:@M@OptionalRequirementOf@objc(pl)SwiftProto"
+// CHECK-NOT: "kind": "requirementOf",{{[[:space:]]*}}"source": "c:@M@OptionalRequirementOf@objc(pl)SwiftProto(im)swiftReq",{{[[:space:]]*}}"target": "c:@M@OptionalRequirementOf@objc(pl)SwiftProto"
 // CHECK-DAG: "kind": "optionalRequirementOf",{{[[:space:]]*}}"source": "c:@M@OptionalRequirementOf@objc(pl)SwiftProto(im)swiftReq",{{[[:space:]]*}}"target": "c:@M@OptionalRequirementOf@objc(pl)SwiftProto"
 
 // SwiftProto.swiftReq -> SwiftProto
-// CHECK-DAG: "kind": "requirementOf",{{[[:space:]]*}}"source": "c:objc(pl)ObjCProto(im)objcReq",{{[[:space:]]*}}"target": "c:objc(pl)ObjCProto"
+// CHECK-NOT: "kind": "requirementOf",{{[[:space:]]*}}"source": "c:objc(pl)ObjCProto(im)objcReq",{{[[:space:]]*}}"target": "c:objc(pl)ObjCProto"
 // CHECK-DAG: "kind": "optionalRequirementOf",{{[[:space:]]*}}"source": "c:objc(pl)ObjCProto(im)objcReq",{{[[:space:]]*}}"target": "c:objc(pl)ObjCProto"
 
 //--- reqs.swift