Use QString literals

This patch covers src/gui and some leftovers from previous commit.

src/base/bittorrent/peeraddress.cpp

@@ -67,9 +67,9 @@ QString PeerAddress::toString() const
         return {};
 
     const QString ipStr = (ip.protocol() == QAbstractSocket::IPv6Protocol)
-        ? ('[' + ip.toString() + ']')
+        ? (u'[' + ip.toString() + u']')
         : ip.toString();
-    return (ipStr + ':' + QString::number(port));
+    return (ipStr + u':' + QString::number(port));
 }
 
 bool BitTorrent::operator==(const BitTorrent::PeerAddress &left, const BitTorrent::PeerAddress &right)

src/base/bittorrent/peerinfo.cpp

@@ -214,7 +214,7 @@ QBitArray PeerInfo::pieces() const
 QString PeerInfo::connectionType() const
 {
     if (m_nativeInfo.flags & lt::peer_info::utp_socket)
-        return QString::fromUtf8(C_UTP);
+        return C_UTP;
 
     return (m_nativeInfo.connection_type == lt::peer_info::standard_bittorrent)
         ? QLatin1String {"BT"}
@@ -316,7 +316,7 @@ void PeerInfo::determineFlags()
 
     // P = Peer is using uTorrent uTP
     if (useUTPSocket())
-        updateFlags(QLatin1Char('P'), QString::fromUtf8(C_UTP));
+        updateFlags(QLatin1Char('P'), C_UTP);
 
     m_flags.chop(1);
     m_flagsDescription.chop(1);

src/base/bittorrent/session.cpp

@@ -5094,7 +5094,7 @@ void Session::handlePeerBlockedAlert(const lt::peer_blocked_alert *p)
         reason = tr("use of privileged port", "this peer was blocked. Reason: use of privileged port.");
         break;
     case lt::peer_blocked_alert::utp_disabled:
-        reason = tr("%1 is disabled", "this peer was blocked. Reason: uTP is disabled.").arg(QString::fromUtf8(C_UTP)); // don't translate μTP
+        reason = tr("%1 is disabled", "this peer was blocked. Reason: uTP is disabled.").arg(C_UTP); // don't translate μTP
         break;
     case lt::peer_blocked_alert::tcp_disabled:
         reason = tr("%1 is disabled", "this peer was blocked. Reason: TCP is disabled.").arg(u"TCP"_qs); // don't translate TCP