docs: Fix known issues unintended nested entries (elastic#17572)

Author: carsonip

docs/release-notes/known-issues.md

@@ -21,13 +21,17 @@ Known issues are significant defects or limitations that may impact your impleme
 :::
 
 :::{dropdown} Tail Sampling may not compact / expired TTLs as quickly as desired, causing increased storage usage.
-**Elastic Stack versions: 8.0.0+ < 9.0**
+
+*Elastic Stack versions: 8.0.0+ < 9.0*
+
 There are some issues with the Tail Sampling implementation in versions 8.0.0+ < 9.0 that may cause the buffered traces to not be compacted or expired as quickly as desired. This can lead to increased storage usage for longer than the default 30m TTL.
 
 This may manifest in two ways, increased value log (vlog) file size and increased SST (LSM) file size. LSM growth and late compaction is particularly troublesome given how the underlying K/V database performs compactions on its layers. There is noticeable LSM growth for use-cases where traces are under 1KB in size, since they are written to the LSM layer directly.
 
 This issue is fixed in 9.0.0, due to a re-implementation of how the underlying tail sampling databases are used. The new implementation uses a more efficient partitioning scheme, allowing more efficient expiration of traces.
 
+:::
+
 :::{dropdown} prefer_ilm required in component templates to create custom lifecycle policies
 
 *Elastic Stack versions: 8.15.1+*