message: Implement clearing above cursor
diff: @@ -1137,8 +1137,20 @@ impl ansi::Handler for Term {
  ansi::ClearMode::All => {
  self.grid.clear(|c| c.reset(&template));
  },
  - _ => {
  - trace!("ansi::ClearMode::Above not implemented");
  + ansi::ClearMode::Above => {
  + // If clearing more than one line
  + if self.cursor.point.line > Line(1) {
  + // Fully clear all lines before the current line
  + for row in &mut self.grid[..self.cursor.point.line] {
  + for cell in row {
  + cell.reset(&template);
  + }
  + }
  + }
  + // Clear up to the current column in the current line
  + for cell in &mut self.grid[self.cursor.point.line][..self.cursor.point.col] {
  + cell.reset(&template);
  + }
  }
  }
  }
  