Improve consistency of overflow warnings (`E039`)

[mhasel]

Is your feature request related to a problem? Please describe.

FUNCTION main : DINT
VAR
    a : INT := 65535; // warning
    b : INT := 16#FFFF; // warning
    c : INT := UINT#16#FFFF; // no warning
    d : INT := WORD#16#FFFF; // no warning
END_VAR

Describe the solution you'd like All of the above expressions evaluate to the same literal 65535, so they should all result in the same warning wenn assigning to INT