Append `display` attributes to doc comments

[JustSimplyKyle]

Essentially, generates a doc comment containg what's in the display when expanding the macro.

HtmlParsingError = {
    #[display("Fails to parse html. Reason: Lack of node id from vdom")]
    /// Fails to parse html. Reason: Lack of node id from vdom
    LackOfNodeid,
};

This allows the lsp to provide a best effort explanation of the error without needing to go to source.

Of course, if the user manually provides the doc comment, use that instead.

[mcmah309]

So if I understand correctly, you are saying if display exists, e.g. #[display("Fails to parse html. Reason: Lack of node id from vdom")] but an explicit doc comment doesn't, then a doc comment of Fails to parse html. Reason: Lack of node id from vdom should be generated, but if a manual doc comment exists, use that instead?

[JustSimplyKyle]

Yes, that's what i'm proposing

[mcmah309]

Yes, I think that could be useful

display like e.g.:
#[display("Missing value of {}", field_name)]
or
#[display("Missing value of {field_name}")]

should probably become

/// Missing value of [`field_name`]