[mid1221213]

Corollary to #15478, which fixes the type alias support for db type, this commit allows the use of an alias to a supported type in a column.

The fix is mainly replacing field.typ occurrences with table.final_type(field.typ) or equivalent.

Example use:

type CountryCode = string

@[table: 'addresses']
pub struct Address {
	id      int @[primary; sql: serial]
	name    string
	address string
	country CountryCode
}

// …

sql db {
	create table Address
} or { panic("don't panic!") }

Created as a draft because all comments welcome and and tests / doc not yet written because of this.

[huly-for-github]

Connected to Huly®: V_0.6-22453

[spytheman]

Please add a test, that checks the intended effect, and that fails on master.