Dereferencing operator . on struct field access

[ironcev]

Description

This PR implements struct field access operator . for references. The overall effort related to references is tracked in #5063.

. is defined for references to structs using this recursive definition: <reference>.<field name> := (*<reference>).<field name>.

This eliminates the need for the dereferencing operator * when working with references to structs:

let s = Struct { x: 0 };

let r = &&&s;

assert((***r).x == r.x);

let r = &&&Struct { r_a: &&A { x: 1 }, &B { y: 2 } ];
assert(r.r_a.x == 1);
assert(r.r_b.y == 2);

Additionally, the PR adds a Diagnostic for the StorageFieldDoesNotExist error and aligns it with the StructFieldDoesNotExist error.

Demo

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Checklist

• I have linked to any relevant issues.
• I have commented my code, particularly in hard-to-understand areas.
• I have updated the documentation where relevant (API docs, the reference, and the Sway book).
• I have added tests that prove my fix is effective or that my feature works.
• I have added (or requested a maintainer to add) the necessary Breaking* or New Feature labels where relevant.
• I have done my best to ensure that my PR adheres to the Fuel Labs Code Review Standards.
• I have requested a review from the relevant team or maintainers.

[tritao]

Looks good! Just some minor nits.