向SourceView增加垂直行号标注
// 设置垂直行号标注
CompositeRuler ruler = new CompositeRuler();
LineNumberRulerColumn lineCol = new LineNumberRulerColumn();
lineCol.setBackground(parent.getShell().getDisplay().getSystemColor(SWT.COLOR_GRAY));
ruler.addDecorator(0, lineCol);
sourceViewer = new SourceViewer(topComp, ruler, SWT.V_SCROLL | SWT.H_SCROLL );