Summary

This PR adds support for serde's #[serde(alias="name")] field-attribute to our options code generator. Simplifying supporting aliases for the same setting.

I'm unsure if we should land this change. I may not end up using it for line-length because I think it's better to actually deprecate these options rather than supporting both (by adding support for Rust's deprecated attribute). However, it is a neat feature and it already works.

Test Plan

I changed line-length to

    /// The line length to use when enforcing long-lines violations (like
    /// `E501`). Must be greater than `0` and less than or equal to `320`.
    #[option(
        default = "88",
        value_type = "int",
        example = r#"
        # Allow lines to be as long as 120 characters.
        line-length = 120
        "#
    )]
    #[serde(alias = "line-width", alias = "max-line-length")]
    pub line_length: Option<LineLength>,

And generated the options markdown