Update duckdb index files

.gitattributes

@@ -58,3 +58,4 @@ General[[:space:]]Knowledge/test/index.duckdb filter=lfs diff=lfs merge=lfs -tex
 Reading[[:space:]]Comprehension/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 Rare[[:space:]]Words/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 Loan[[:space:]]Words/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
+Standard[[:space:]]Nomenclature/test/index.duckdb filter=lfs diff=lfs merge=lfs -text

Standard Nomenclature/test/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:f968cd4607336c7656aee0caa7906170809bb218fd453a8c0bb606ce95ccc344
+size 1060864