refactor: add explicit this-> where possible

I have knowingly skipped some files/portions of files where this would
create merge conflicts for other open PRs.

src/providers/twitch/ChannelPointReward.cpp

@@ -58,13 +58,13 @@ ChannelPointReward::ChannelPointReward(const QJsonObject &redemption)
     }
 
     // use bits cost when channel points were not used
-    if (cost == 0)
+    if (this->cost == 0)
     {
         this->cost = reward.value("bits_cost").toInt();
     }
 
     // workaround twitch bug where bits_cost is always 0 in practice
-    if (cost == 0)
+    if (this->cost == 0)
     {
         this->cost = reward.value("default_bits_cost").toInt();
     }

src/providers/twitch/EmoteValue.hpp

@@ -8,17 +8,17 @@ struct EmoteValue {
 public:
     int getSet()
     {
-        return set_;
+        return this->set_;
     }
 
     int getId()
     {
-        return id_;
+        return this->id_;
     }
 
     const QString &getChannelName()
     {
-        return channelName_;
+        return this->channelName_;
     }
 
 private:

src/providers/twitch/TwitchChannel.cpp

@@ -1196,7 +1196,7 @@ void TwitchChannel::updateSeventvUser(
         return;
     }
 
-    updateSeventvData(this->seventvUserID_, dispatch.emoteSetID);
+    this->updateSeventvData(this->seventvUserID_, dispatch.emoteSetID);
     SeventvEmotes::getEmoteSet(
         dispatch.emoteSetID,
         [this, weak = weakOf<Channel>(this), dispatch](auto &&emotes,

src/providers/twitch/api/Helix.hpp

@@ -393,7 +393,7 @@ struct HelixBadgeSet {
         const auto jsonVersions = json.value("versions").toArray();
         for (const auto &version : jsonVersions)
         {
-            versions.emplace_back(version.toObject());
+            this->versions.emplace_back(version.toObject());
         }
     }
 };

src/providers/twitch/eventsub/MessageBuilder.cpp

@@ -161,9 +161,9 @@ void EventSubMessageBuilder::appendUser(const lib::String &userName,
                                         QString &text, bool trailingSpace)
 {
     auto login = userLogin.qt();
-    auto *el = this->emplace<MentionElement>(userName.qt(), login,
-                                             MessageColor::System,
-                                             channel->getUserColor(login));
+    auto *el = this->emplace<MentionElement>(
+        userName.qt(), login, MessageColor::System,
+        this->channel->getUserColor(login));
     text.append(login);
 
     if (trailingSpace)

src/providers/twitch/eventsub/SubscriptionHandle.cpp

@@ -19,7 +19,7 @@ RawSubscriptionHandle::~RawSubscriptionHandle()
         // We're shutting down, assume the unsubscription has been taken care of
         return;
     }
-    app->getEventSub()->removeRef(request);
+    app->getEventSub()->removeRef(this->request);
 }
 
 }  // namespace chatterino::eventsub