refactor: Run use Children

apirun.go

@@ -20,8 +20,6 @@
 
 package docxlib
 
-import "encoding/xml"
-
 // Color allows to set run color
 func (r *Run) Color(color string) *Run {
 	r.RunProperties.Color = &Color{
@@ -42,16 +40,6 @@ func (r *Run) Size(size string) *Run {
 
 // AddTab add a tab in front of the run
 func (r *Run) AddTab() *Run {
-	r.FrontTab = append(r.FrontTab, struct {
-		XMLName xml.Name "xml:\"w:tab,omitempty\""
-	}{})
-	return r
-}
-
-// AppendTab add a tab after the run
-func (r *Run) AppendTab() *Run {
-	r.RearTab = append(r.RearTab, struct {
-		XMLName xml.Name "xml:\"w:tab,omitempty\""
-	}{})
+	r.Children = append(r.Children, &WTab{})
 	return r
 }