Elide text from the right for all columns' header

Minimizing columns no longer truncates text from the left, now elides
text from the right for better readability. Done by setting header's
textElideMode to Qt::TextElideRight.

Fix issue #14419.
PR #15366.

src/gui/torrentcontenttreeview.cpp

@@ -72,6 +72,7 @@ TorrentContentTreeView::TorrentContentTreeView(QWidget *parent)
     unused.setVerticalHeader(header());
     header()->setParent(this);
     header()->setStretchLastSection(false);
+    header()->setTextElideMode(Qt::ElideRight);
     unused.setVerticalHeader(new QHeaderView(Qt::Horizontal));
 }