Provide more propositions for DTYP field

[vnadot]

Today we have only 2 proposals:

field(DTYP, \"${1|Soft Channel,stream|}

[vnadot]

Waiting for a list.

[anjohnson]

Legal values for a DTYP field depend on the set of device supports attached to a particular record type; you can't be sure what values a particular IOC will accept without parsing the generated DBD file that the IOC will be loading (and that probably isn't something that this module could do, just identifying which DBD file to parse isn't simple). Most (but not all) record types in Base support Soft Channel, Raw Soft Channel and/or Async Soft Channel, but a few record types don't have any device support at all and the IOC will reject any values except 0 or an empty string for those record types.