feat: /clearmessages command (#2485)

CHANGELOG.md

@@ -7,6 +7,7 @@
 - Major: Added Streamer Mode configuration (under `Settings -> General`), where you can select which features of Chatterino should behave differently when you are in Streamer Mode. (#2001, #2316, #2342, #2376)
 - Major: Color mentions to match the mentioned users. You can disable this by unchecking "Color @usernames" under `Settings -> General -> Advanced (misc.)`. (#1963, #2284)
 - Major: Commands `/ignore` and `/unignore` have been renamed to `/block` and `/unblock` in order to keep consistency with Twitch's terms. (#2370)
+- Minor: Added `/clearmessages` command - does what "Burger menu -> More -> Clear messages" does. (#2485)
 - Minor: Added `/marker` command - similar to webchat, it creates a stream marker. (#2360)
 - Minor: Added `/chatters` command showing chatter count. (#2344)
 - Minor: Added a button to the split context menu to open the moderation view for a channel when the account selected has moderator permissions. (#2321)

src/controllers/commands/CommandController.cpp

@@ -22,6 +22,7 @@
 #include "util/Twitch.hpp"
 #include "widgets/Window.hpp"
 #include "widgets/dialogs/UserInfoPopup.hpp"
+#include "widgets/splits/Split.hpp"
 
 #include <QApplication>
 #include <QFile>
@@ -633,6 +634,16 @@ void CommandController::initialize(Settings &, Paths &paths)
 
             return "";
         });
+
+    this->registerCommand("/clearmessages", [](const auto & /*words*/,
+                                               ChannelPtr channel) {
+        auto *currentPage = dynamic_cast<SplitContainer *>(
+            getApp()->windows->getMainWindow().getNotebook().getSelectedPage());
+
+        currentPage->getSelectedSplit()->getChannelView().clearMessages();
+
+        return "";
+    });
 }
 
 void CommandController::save()