Update opentelemetry-sdk/src/metrics/pipeline.rs

Author: utpilla

opentelemetry-sdk/src/metrics/pipeline.rs

@@ -364,7 +364,7 @@ where
         mut stream: Stream,
     ) -> MetricResult<Option<Arc<dyn internal::Measure<T>>>> {
         // TODO: Create a separate pub (crate) Stream struct for the pipeline,
-        // as Stream will not have any Optional fields as None at this point and
+        // as Stream will not have any optional fields as None at this point and
         // new struct can better reflect this.
         let mut agg = stream
             .aggregation