Update duckdb index files

.gitattributes

@@ -64,3 +64,4 @@ anime.stackexchange.com_simple/train/index.duckdb filter=lfs diff=lfs merge=lfs
 ja.stackoverflow.com/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 ja.stackoverflow.com_simple/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 japanese.stackexchange.com/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
+japanese.stackexchange.com_simple/train/index.duckdb filter=lfs diff=lfs merge=lfs -text

japanese.stackexchange.com_simple/train/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:161beb02fb3af8287eff3cd9514d382e80c8b6a6984f15fcd51f9a9559166f56
+size 136327168