Apply consistent UType field descriptions

[nils-work]

As noted in the MI20 Holistic issue, all UType field descriptions could follow a standardised format for consistency and improved interpretation.

Apply the change noted in the MI20 holistic feedback issue:

The "Reference to the applicable [type] structure." convention could be applied to all ...UType field descriptions for consistency and clarity of interpretation.

The following sample shows the current variation across schemas:

• The type of recurrence used to define the schedule.
• The type of structure to present account specific fields.
• Indicator of the type of transaction object present in this record
• The type of address object present
• The type of object present in this response (from EnergyPaymentSchedule)
• Type of object included that describes the payee in detail.
• The type of customer object that is present
• Type of account object included.

This style was applied to the field noted here.