fixed reference extraction

rag.py

@@ -365,6 +365,12 @@ def extract_reference(url):
         return url.split("blob/main/")[-1]
     elif "tree/main" in url:
         return url.split("tree/main/")[-1] or "root"
+    elif "blob/master" in url:
+        return url.split("blob/master/")[-1]
+    elif "tree/master" in url:
+        return url.split("tree/master/")[-1] or "root"
+    elif "refs/heads/master" in url:
+        return url.split("refs/heads/master/")[-1]
     return url
 
 # Join content pages for processing