Automatically load recent messages on reconnect (#3878)

* Add working reconnect recent messages

* Rename method to messagesUpdated

* Use audo declarations

* Add docs to new LimitedQueue methods

* Add more documentation, try atomic loading flag

* Update CHANGELOG.md

* Remove unused include

* Rename 'reconnected' signal to 'connected'

* Reserve before filtering on arbitrary update

* Extract recent messages fetching to own class

* Use std::atomic_flag instead of std::atomic_bool

* Add PostToThread include

* Add chatterino.recentmessages logging

* Remove unneeded parameters, lambda move capture

* Remove TwitchChannel::buildRecentMessages

* Add documentation, use more clear method name

* Reword changelog entry

I think it sounds better like this :)

* Rework how filling in missing messages is handled

This should hopefully prevent issues with filtered channels with old messages
that no longer exist in the underlying channel

* Check existing messages when looking for reply

* Clean up string distribution in file

* Try to improve documentation

* Use std::function for RecentMessagesApi

* Only trigger filledInMessages if we inserted

* Remove old unused lines

* Use make_shared<MessageLayout> instead of new MessageLayout

* Alphabetize QLogging categories

* Reorder CHANGELOG.md

src/providers/twitch/TwitchChannel.hpp

@@ -21,6 +21,7 @@
 #include <boost/signals2.hpp>
 #include <pajlada/signals/signalholder.hpp>
 
+#include <atomic>
 #include <mutex>
 #include <unordered_map>
 
@@ -163,6 +164,7 @@ private:
     void refreshBadges();
     void refreshCheerEmotes();
     void loadRecentMessages();
+    void loadRecentMessagesReconnect();
     void fetchDisplayName();
     void cleanUpReplyThreads();
     void showLoginMessage();
@@ -188,6 +190,7 @@ private:
     int chatterCount_;
     UniqueAccess<StreamStatus> streamStatus_;
     UniqueAccess<RoomModes> roomModes_;
+    std::atomic_flag loadingRecentMessages_ = ATOMIC_FLAG_INIT;
     std::unordered_map<QString, std::weak_ptr<MessageThread>> threads_;
 
 protected: