Adding span metrics link to trace explorer docs (#13675)

## DESCRIBE YOUR PR
Fixing the linting issue from this branch
(#13652) and updating trace
explorer docs with a link.

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---------

Co-authored-by: Shannon Anahata <[email protected]>

Author: sfanahata

docs/product/explore/trace-explorer/index.mdx

@@ -26,7 +26,7 @@ The [**Trace Explorer**](https://sentry.io/orgredirect/organizations/:orgslug/tr
 
 ### Span Metrics
 
-- Span metrics are derived from applying a function to your span attributes (default or custom), like `p50(cart.value)` or `sum(ai.token_use)`, over a granular time frame. This calculation extrapolates metrics that then populate dashboards, alerts, etc. based on that rolling time window.
+- [Span metrics](/concepts/key-terms/tracing/span-metrics/) are derived from applying a function to your span attributes (default or custom), like `p50(cart.value)` or `sum(ai.token_use)`, over a granular time frame. This calculation extrapolates metrics that then populate dashboards, alerts, etc. based on that rolling time window.
 - These 'metrics' aren't stored separately from your span data. Rather, they're queried on the fly. This reduces your need to manage, ingest, and store custom metrics.
 
 ## Practical Examples