refactor: replace ISelectionPosition with IBufferRange

See xtermjs/xterm.js#3952

src/main/resources/META-INF/frontend/fc-xterm/xterm-selection-mixin.ts

@@ -97,12 +97,12 @@ class SelectionAddon extends TerminalAddon<ISelectionMixin> {
  let buffer = (terminal.buffer.active as any)._buffer;
  let range = buffer.getWrappedRangeForLine(buffer.ybase+buffer.y);
 
- let pos = terminal.getSelectionPosition() || {startRow: buffer.ybase+buffer.y, startColumn: buffer.x};
+ let pos = terminal.getSelectionPosition() || {start: {y: buffer.ybase+buffer.y, x: buffer.x}};
 
  resetSelection();
  ensureSelection();
  let dx = range.first * terminal.cols - this.__selectionAnchor!;
- if (pos.startRow != range.first || pos.startColumn != promptLength()) {
+ if (pos.start.y != range.first || pos.start.x != promptLength()) {
  dx+= promptLength();
  }
 
@@ -126,8 +126,7 @@ class SelectionAddon extends TerminalAddon<ISelectionMixin> {
  let buffer = (terminal.buffer.active as any)._buffer;
  let range = buffer.getWrappedRangeForLine(buffer.ybase+buffer.y); 
  let pos = terminal.getSelectionPosition(); 
- if (pos && pos.startRow>=range.first && pos.endRow<=range.last) {
- //let selectionStart = pos.startRow * terminal.cols + pos.startColumn;
+ if (pos && pos.start.y>=range.first && pos.end.y<=range.last) {
  if (!this.__selectionRight) {
  //cursor backward wrapped
  terminal.write("\x1b[<" + this.__selectionLength + "L");