enum aliases support is broken

[pompon0]

For example for:

enum AliasedEnum {
    option allow_alias = true;

    ALIAS_FOO = 0;
    ALIAS_BAR = 1;
    ALIAS_BAZ = 2;
    MOO = 2;
    moo = 2;
    bAz = 2;
}

pbjson_build generates:

impl serde::Serialize for AliasedEnum {
    #[allow(deprecated)]
    fn serialize<S>(&self, serializer: S) -> std::result::Result<S::Ok, S::Error>
    where
        S: serde::Serializer,
    {
        let variant = match self {
            Self::AliasFoo => "ALIAS_FOO",
            Self::AliasBar => "ALIAS_BAR",
            Self::AliasBaz => "ALIAS_BAZ",
            Self::Moo => "MOO",
            Self::Moo => "moo",
            Self::BAz => "bAz",
        };
        serializer.serialize_str(variant)
    }
}

while prost-build generates:

    #[repr(i32)]
    pub enum AliasedEnum {
        AliasFoo = 0,
        AliasBar = 1,
        AliasBaz = 2,
    }

i.e. pbjson_build incorrectly assumes that there are no aliases and thinks that each alias has its own rust enum variant.

[tustvold]

Closed by #103