Rust: Test more variants of rusqlite usage.

rust/ql/test/library-tests/frameworks/rusqlite/main.rs

@@ -48,5 +48,13 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
         })
     })?;
 
+    _ = connection.prepare_cached("SELECT id, name, age FROM person")?; // $ MISSING: sql-sink
+    _ = connection.prepare_with_flags("SELECT id, name, age FROM person", rusqlite::PrepFlags::empty())?; // $ MISSING: ql-sink
+    _ = connection.query_row_and_then("SELECT id, name, age FROM person", [], |row| { // $ sql-sink
+        let row: &rusqlite::Row<'_> = row;
+        let result: Result<i32, rusqlite::Error> = Ok(row.get(0)?); // $ database-read
+        result
+    })?;
+
     Ok(())
 }