Properly accept relayChain and paraId spellings

[tomaka]

Fix #42

I think that serde isn't working as intended, so let's do it differently.

[github-actions]

twiggy diff report

Difference in .wasm size before and after this pull request.

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 Delta Bytes │ Item
─────────────┼─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
       +8908 ┊ <&mut serde_json::de::Deserializer<R> as serde::de::Deserializer>::deserialize_struct::hbe18de873609fa22
       -6947 ┊ <&mut serde_json::de::Deserializer<R> as serde::de::Deserializer>::deserialize_map::h9041dd7566242c91
       +1750 ┊ <&mut serde_json::de::Deserializer<R> as serde::de::Deserializer>::deserialize_struct::hdadbf8be62f41665
       -1418 ┊ <&mut serde_json::de::Deserializer<R> as serde::de::Deserializer>::deserialize_any::hc89f23a8401b568c
       -1264 ┊ <&mut serde_json::de::Deserializer<R> as serde::de::Deserializer>::deserialize_struct::h6fe23d4154a85cf0
        -740 ┊ <serde::__private::de::content::ContentVisitor as serde::de::Visitor>::visit_map::h4c95274b1ace3ba3
        -711 ┊ <serde::__private::de::FlatMapDeserializer<E> as serde::de::Deserializer>::deserialize_struct::h3e6b02829e170422
        -668 ┊ serde::__private::de::content::ContentDeserializer<E>::deserialize_integer::hd90dbc23b3ab7d74
        -624 ┊ <serde_json::de::MapAccess<R> as serde::de::MapAccess>::next_key_seed::h8484a33a28c30a95
        +598 ┊ <serde_json::de::MapAccess<R> as serde::de::MapAccess>::next_key_seed::h1c4a781f212cad5f
        -598 ┊ <serde_json::de::MapAccess<R> as serde::de::MapAccess>::next_key_seed::h3ce06dd0376bde3c
        +598 ┊ <serde_json::de::MapAccess<R> as serde::de::MapAccess>::next_key_seed::hae01d0a6e3918b25
        +564 ┊ smoldot::chain_spec::structs::_::<impl serde::de::Deserialize for smoldot::chain_spec::structs::ChainType>::deserialize::h786365b49674ae56
        -564 ┊ smoldot::chain_spec::structs::_::<impl serde::de::Deserialize for smoldot::chain_spec::structs::ChainType>::deserialize::h7feb4c808c15df6e
        -561 ┊ <smoldot::chain_spec::structs::_::<impl serde::de::Deserialize for smoldot::chain_spec::structs::ChainSpecParachain>::deserialize::__FieldVisitor as serde::de::Visitor>::visit_bytes::h98ebfff2f972f7f1
        +541 ┊ smoldot::chain_spec::structs::_::<impl serde::de::Deserialize for smoldot::chain_spec::structs::Genesis>::deserialize::h4b0a570043244266
        -541 ┊ smoldot::chain_spec::structs::_::<impl serde::de::Deserialize for smoldot::chain_spec::structs::Genesis>::deserialize::h5cb2cae2c02fa345
        -524 ┊ <serde_json::de::MapAccess<R> as serde::de::MapAccess>::next_key_seed::haf6ed7f41e3a65f8
        -501 ┊ <serde::__private::de::FlatStructAccess<E> as serde::de::MapAccess>::next_key_seed::h50382b4e10551d36
        -491 ┊ <smoldot::chain_spec::structs::_::<impl serde::de::Deserialize for smoldot::chain_spec::structs::ClientSpec>::deserialize::__FieldVisitor as serde::de::Visitor>::visit_borrowed_str::hb3d12e5c6cfba45c
       +1466 ┊ ... and 113 more.
       -6521 ┊ Σ [133 Total Rows]