From lxde/qtermwidget@60221da by @yan12125: Support ECMA-48 REP. I tried to make the changes follow existing styles and conventions.
ECMA-48 8.3.103 describes the sequence CSI Pₙ b for repeating the previous character in the data stream. This sequence has been present in XTerm since January 1997 and has been added to the latest terminfo entry for xterm-new and derived entries such as xterm-256color.