refactor: remove unused functions detected by cppcheck

Note: Some more functions were detected, but this are the ones I'm
pretty sure we don't need.

src/widget/widget.cpp

@@ -1213,16 +1213,6 @@ void Widget::onFriendMessageReceived(int friendId, const QString& message, bool
     newFriendMessageAlert(friendId);
 }
 
-void Widget::onReceiptRecieved(int friendId, ReceiptNum receipt)
-{
-    Friend* f = FriendList::findFriend(friendId);
-    if (!f) {
-        return;
-    }
-
-    chatForms[friendId]->getOfflineMsgEngine()->onReceiptReceived(receipt);
-}
-
 void Widget::addFriendDialog(const Friend* frnd, ContentDialog* dialog)
 {
     uint32_t friendId = frnd->getId();
@@ -1551,21 +1541,6 @@ void Widget::removeFriend(int friendId)
     removeFriend(FriendList::findFriend(friendId), false);
 }
 
-void Widget::clearContactsList()
-{
-    assert(QThread::currentThread() == qApp->thread());
-
-    QList<Friend*> friends = FriendList::getAllFriends();
-    for (Friend* f : friends) {
-        removeFriend(f, true);
-    }
-
-    QList<Group*> groups = GroupList::getAllGroups();
-    for (Group* g : groups) {
-        removeGroup(g, true);
-    }
-}
-
 void Widget::onDialogShown(GenericChatroomWidget* widget)
 {
     widget->resetEventFlags();
@@ -2355,21 +2330,6 @@ void Widget::searchCircle(CircleWidget* circleWidget)
     circleWidget->search(text, true, filterOnline(filter), filterOffline(filter));
 }
 
-void Widget::searchItem(GenericChatItemWidget* chatItem, GenericChatItemWidget::ItemType type)
-{
-    bool hide;
-    FilterCriteria filter = getFilterCriteria();
-    switch (type) {
-    case GenericChatItemWidget::GroupItem:
-        hide = filterGroups(filter);
-        break;
-    default:
-        hide = true;
-    }
-
-    chatItem->searchName(ui->searchContactText->text(), hide);
-}
-
 bool Widget::groupsVisible() const
 {
     FilterCriteria filter = getFilterCriteria();

src/widget/widget.h

@@ -122,7 +122,6 @@ public:
     bool newGroupMessageAlert(int groupId, bool notify);
     bool getIsWindowMinimized();
     void updateIcons();
-    void clearContactsList();
 
     static QString fromDialogType(DialogType type);
     ContentDialog* createContentDialog() const;
@@ -141,7 +140,6 @@ public:
     static Status getStatusFromString(QString status);
 
     void searchCircle(CircleWidget* circleWidget);
-    void searchItem(GenericChatItemWidget* chatItem, GenericChatItemWidget::ItemType type);
     bool groupsVisible() const;
 
     void resetIcon();
@@ -170,7 +168,6 @@ public slots:
     void onFriendMessageReceived(int friendId, const QString& message, bool isAction);
     void onFriendRequestReceived(const ToxPk& friendPk, const QString& message);
     void updateFriendActivity(const Friend* frnd);
-    void onReceiptRecieved(int friendId, ReceiptNum receipt);
     void onEmptyGroupCreated(int groupId, const QString& title);
     void onGroupInviteReceived(const GroupInvite& inviteInfo);
     void onGroupInviteAccepted(const GroupInvite& inviteInfo);