cleaned up bg props

Signed-off-by: Charles de Dreuille <charles.dedreuille@gmail.com>

.changeset/alert-remove-surface.md

@@ -10,3 +10,5 @@ The Alert component's background is now driven entirely by its `status` prop. Th
 - <Alert surface="1" status="info" />
 + <Alert status="info" />
 ```
+
+**Affected components:** Alert

.changeset/clean-bags-occur.md

@@ -86,6 +86,6 @@ Update CSS selectors targeting surface data attributes:
 + [data-on-bg='neutral-1'] { ... }
 ```
 
-Note: Provider components use `data-bg` (values: `neutral-1` through `neutral-3`, plus intents). Consumer components use `data-on-bg`, which reflects the parent container's bg directly (no auto-increment).
+Note: Provider components use `data-bg` (values: `neutral-1` through `neutral-3`, plus intents). Consumer components use `data-on-bg`, which reflects the parent container's `bg` directly.
 
 **Affected components:** Box, Button, ButtonIcon, ButtonLink, ToggleButton, Card, Flex, Grid