Update src/parser/merge.rs

Co-authored-by: Ifeanyi Ubah <ify1992@yahoo.com>

Author: xitep

src/parser/merge.rs

@@ -10,7 +10,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//! SQL Parser for MERGE
+//! SQL Parser for a `MERGE` statement
 
 #[cfg(not(feature = "std"))]
 use alloc::{boxed::Box, format, string::ToString, vec, vec::Vec};