Dictionary FixedString as key column data type.

[UnamedRus]

Use case

Ability to use FixedString in dictionary key column.

Describe the solution you'd like

CREATE DICTIONARY dict (
key FixedString(3),
....
)
PRIMARY KEY key
....

There was an error on xxx: Code: 50. DB::Exception: Unknown type FixedString(3) for dictionary attribute.

Describe alternatives you've considered

Use String instead, but may be it's less efficient.

Additional context

Add any other context or screenshots about the feature request here.