Update docs/product/tracing/span-metrics/index.mdx

Co-authored-by: Alex Krawiec <[email protected]>

Author: codyde

docs/product/tracing/span-metrics/index.mdx

@@ -71,7 +71,7 @@ There are two primary methods for implementing span metrics:
 
 ### 1. Enhancing Existing Spans
 
-Augment automatically created or manually defined spans with additional metric attributes:
+Augment automatically-created or manually-defined spans with additional metric attributes:
 
 ```javascript
 // Adding metrics to an existing file upload span