minor corrections to span metric details

Author: codyde

docs/platforms/javascript/common/tracing/span-metrics/index.mdx

@@ -41,11 +41,11 @@ When adding metrics as span attributes:
 
 - Use consistent naming conventions (for example, `category.metric_name`)
 - Keep attribute names concise but descriptive
-- Use appropriate data types (string, number, boolean, or (non-mixed) arrays of these types)
+- Use appropriate data types (string, number, boolean, or an array containing only one of these types)
 
 ## Creating Dedicated Metric Spans
 
-For more detailed operations, task, or process tracking, you can create custom dedicated spans that focus on specific metrics or attributes that you want to track. This approach provides better discoverability and more precise span configurations, however it can also appear to create more noise in your trace waterfall.
+For more detailed operations, tasks, or process tracking, you can create custom dedicated spans that focus on specific metrics or attributes that you want to track. This approach provides better discoverability and more precise span configurations, however it can also create more noise in your trace waterfall.
 
 ```javascript
 Sentry.startSpan(