emit short and long versions of user given types

[Vindaar]

Works around the following:

    defUnit(ft²•ft⁻³)
    let x = 1.m⁻¹
    check x.to(ft²•ft⁻³) == 0.3048.ft⁻¹
    check x.to(ft²•ft⁻³) == 0.3048.ft²•ft⁻³

now producing problems as we emit the long form of user given types later. Those were not defined, because we only define long versions of the reduced version, i.e. Foot⁻¹.