docs: update creating-your-first-dashboard.mdx (#29631)

(cherry picked from commit 2a9a1d3)

docs/docs/using-superset/creating-your-first-dashboard.mdx

@@ -106,7 +106,7 @@ You can also certify metrics if you'd like for your team in this view.
 
 2. Virtual calculated columns: you can write SQL queries that
 customize the appearance and behavior
-of a specific column (e.g. `CAST(recovery_rate) as float`).
+of a specific column (e.g. `CAST(recovery_rate as float)`).
 Aggregate functions aren't allowed in calculated columns.
 
 <img src={useBaseUrl("/img/tutorial/tutorial_calculated_column.png" )} />