Fix MDX parsing error in mapping.mdx by escaping curly braces

Co-authored-by: hotlong <50353452+hotlong@users.noreply.github.com>

Author: Copilot

content/docs/references/data/mapping.mdx

@@ -41,7 +41,7 @@ const result = MappingSchema.parse(data);
 | **fromField** | `string` | optional | Match on field (e.g. "name") for lookup |
 | **toField** | `string` | optional | Value to take (e.g. "_id") for lookup |
 | **autoCreate** | `boolean` | optional | Create if missing for lookup |
-| **valueMap** | `Record<string, any>` | optional | Value mapping for map transform (e.g. { "Open": "draft" }) |
+| **valueMap** | `Record<string, any>` | optional | Value mapping for map transform (e.g. `{ "Open": "draft" }`) |
 | **separator** | `string` | optional | Separator for split/join transforms |
 
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