Update docs/financial/financialentities.md

Co-Authored-By: Mikey O'Toole <mikey@mjco.uk>

docs/financial/financialentities.md

@@ -84,5 +84,5 @@ adjustment line items being created in these cases. The issue is that the civicr
 
 This means that if a line item with no `price_field_values` (i.e: a text / enter quantity line item) is altered it is not possible
 to create a reversal line and a new line within the schema. The same problem occurs when changing a line item with price_field_values
-BACK to a price_field_value it previously held. In both these scenarios the work around is to have more than one 'valid' financial_item
+***back*** to a `price_field_value` it previously held. In both these scenarios the work around is to have more than one *valid* `financial_item`
 against the resulting line item with an 'adjustment' entry -  ie an additional financial_item.