Implement associative center mark workflow

src/entities/traits.rs

@@ -111,6 +111,14 @@ pub trait TextContent {
 pub fn entity_type_name(et: &EntityType) -> &str {
     match et {
         EntityType::Point(_) => "Point",
+        EntityType::Line(line)
+            if acadrust::entities::CenterMarkAssociation::read(
+                &line.common.extended_data,
+            )
+            .is_some() =>
+        {
+            "CenterMark"
+        }
         EntityType::Line(line)
             if acadrust::entities::CenterLineAssociation::read(
                 &line.common.extended_data,