Remove "talking to" prefix from private chats

Additionally, use the same name for “private chat“ in all menus (we had
“personal talk” and “direct chat“ before)

cockatrice/src/tab_message.cpp

@@ -51,7 +51,7 @@ void TabMessage::addMentionTag(QString mentionTag) {
 
 void TabMessage::retranslateUi()
 {
-    messageMenu->setTitle(tr("Personal &talk"));
+    messageMenu->setTitle(tr("Private &chat"));
     aLeave->setText(tr("&Leave"));
 }
 
@@ -68,7 +68,7 @@ QString TabMessage::getUserName() const
 
 QString TabMessage::getTabText() const
 {
-    return tr("Talking to %1").arg(QString::fromStdString(otherUserInfo->name()));
+    return tr("%1 - Private chat").arg(QString::fromStdString(otherUserInfo->name()));
 }
 
 void TabMessage::closeRequest()

cockatrice/src/user_context_menu.cpp

@@ -38,7 +38,7 @@ UserContextMenu::UserContextMenu(const TabSupervisor *_tabSupervisor, QWidget *p
 void UserContextMenu::retranslateUi()
 {
     aDetails->setText(tr("User &details"));
-    aChat->setText(tr("Direct &chat"));
+    aChat->setText(tr("Private &chat"));
     aShowGames->setText(tr("Show this user's &games"));
     aAddToBuddyList->setText(tr("Add to &buddy list"));
     aRemoveFromBuddyList->setText(tr("Remove from &buddy list"));