Fix weight template to remove ugliness in rust doc (#7565)

fixed weight template 

substrate/.maintain/frame-weight-template.hbs

@@ -15,7 +15,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//! Weights for {{pallet}}
+//! Autogenerated weights for {{pallet}}
+//!
 //! THIS FILE WAS AUTO-GENERATED USING THE SUBSTRATE BENCHMARK CLI VERSION {{version}}
 //! DATE: {{date}}, STEPS: {{cmd.steps}}, REPEAT: {{cmd.repeat}}, LOW RANGE: {{cmd.lowest_range_values}}, HIGH RANGE: {{cmd.highest_range_values}}
 //! EXECUTION: {{cmd.execution}}, WASM-EXECUTION: {{cmd.wasm_execution}}, CHAIN: {{cmd.chain}}, DB CACHE: {{cmd.db_cache}}

substrate/utils/frame/benchmarking-cli/src/template.hbs

 {{header}}
-//! Weights for {{pallet}}
+//! Autogenerated weights for {{pallet}}
+//!
 //! THIS FILE WAS AUTO-GENERATED USING THE SUBSTRATE BENCHMARK CLI VERSION {{version}}
 //! DATE: {{date}}, STEPS: {{cmd.steps}}, REPEAT: {{cmd.repeat}}, LOW RANGE: {{cmd.lowest_range_values}}, HIGH RANGE: {{cmd.highest_range_values}}
 //! EXECUTION: {{cmd.execution}}, WASM-EXECUTION: {{cmd.wasm_execution}}, CHAIN: {{cmd.chain}}, DB CACHE: {{cmd.db_cache}}