fix dupe search with included formatting

https://anki.tenderapp.com/discussions/ankidesktop/41286-2125-doesnt-show-duplicates

rslib/src/search/sqlwriter.rs

@@ -362,7 +362,7 @@ impl SqlWriter<'_> {
         let csum = field_checksum(text_nohtml.as_ref());
         write!(
             self.sql,
-            "(n.mid = {} and n.csum = {} and field_at_index(n.flds, 0) = ?)",
+            "(n.mid = {} and n.csum = {} and n.sfld = ?)",
             ntid, csum
         )
         .unwrap();