kernel/server_session: Return a std::pair from CreateSessionPair()

Keeps the return type consistent with the function name. While we're at
it, we can also reduce the amount of boilerplate involved with handling
these by using structured bindings.

src/core/hle/ipc_helpers.h

@@ -139,10 +139,8 @@ public:
             context->AddDomainObject(std::move(iface));
         } else {
             auto& kernel = Core::System::GetInstance().Kernel();
-            auto sessions =
+            auto [server, client] =
                 Kernel::ServerSession::CreateSessionPair(kernel, iface->GetServiceName());
-            auto server = std::get<Kernel::SharedPtr<Kernel::ServerSession>>(sessions);
-            auto client = std::get<Kernel::SharedPtr<Kernel::ClientSession>>(sessions);
             iface->ClientConnected(server);
             context->AddMoveObject(std::move(client));
         }

src/core/hle/kernel/client_port.cpp

@@ -2,8 +2,6 @@
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
-#include <tuple>
-
 #include "core/hle/kernel/client_port.h"
 #include "core/hle/kernel/client_session.h"
 #include "core/hle/kernel/errors.h"
@@ -31,18 +29,18 @@ ResultVal<SharedPtr<ClientSession>> ClientPort::Connect() {
     active_sessions++;
 
     // Create a new session pair, let the created sessions inherit the parent port's HLE handler.
-    auto sessions = ServerSession::CreateSessionPair(kernel, server_port->GetName(), this);
+    auto [server, client] = ServerSession::CreateSessionPair(kernel, server_port->GetName(), this);
 
     if (server_port->HasHLEHandler()) {
-        server_port->GetHLEHandler()->ClientConnected(std::get<SharedPtr<ServerSession>>(sessions));
+        server_port->GetHLEHandler()->ClientConnected(server);
     } else {
-        server_port->AppendPendingSession(std::get<SharedPtr<ServerSession>>(sessions));
+        server_port->AppendPendingSession(server);
     }
 
     // Wake the threads waiting on the ServerPort
     server_port->WakeupAllWaitingThreads();
 
-    return MakeResult(std::get<SharedPtr<ClientSession>>(sessions));
+    return MakeResult(client);
 }
 
 void ClientPort::ConnectionClosed() {

src/core/hle/kernel/server_session.cpp

@@ -204,6 +204,6 @@ ServerSession::SessionPair ServerSession::CreateSessionPair(KernelCore& kernel,
     client_session->parent = parent;
     server_session->parent = parent;
 
-    return std::make_tuple(std::move(server_session), std::move(client_session));
+    return std::make_pair(std::move(server_session), std::move(client_session));
 }
 } // namespace Kernel

src/core/hle/kernel/server_session.h

@@ -6,6 +6,7 @@
 
 #include <memory>
 #include <string>
+#include <utility>
 #include <vector>
 
 #include "core/hle/kernel/object.h"
@@ -58,7 +59,7 @@ public:
         return parent.get();
     }
 
-    using SessionPair = std::tuple<SharedPtr<ServerSession>, SharedPtr<ClientSession>>;
+    using SessionPair = std::pair<SharedPtr<ServerSession>, SharedPtr<ClientSession>>;
 
     /**
      * Creates a pair of ServerSession and an associated ClientSession.