Add sql syntax highlighting to the latest til.

postgres/truncate-all-rows.md

@@ -3,7 +3,7 @@
 Given a postgres database, if you want to delete all rows in a table, you
 can use the `DELETE` query without any conditions.
 
-```
+```sql
 > delete from pokemons;
 DELETE 151
 ```
@@ -13,7 +13,7 @@ out a table, you are better off using `TRUNCATE`. A `TRUNCATE` query will be
 faster than a `DELETE` query because it will just delete the rows without
 scanning them as it goes.
 
-```
+```sql
 > truncate pokemons;
 TRUNCATE TABLE
 ```