Implement attribute support into New function.

[krypt102]

This PR fixes #1 with a relatively simple API to use.
Attributes can be implemented as follows:

local stateValue = Value("AttributeValue2")

local folder = New "Folder" {
    [Attribute "AttributeName"] = "AttributeValue",
    [Attribute "AttributeName2"] = stateValue
} 

Attribute supports state binding, meaning if you set an attribute to a state value, it will automatically update when that state value changes.

AttributeChanged works similarly to OnChange, where you give it an attribute name, and when that attribute changes, it will run your specified callback.

local child = New "Folder" {
    [Attribute "Test"] = "AttributeOne",
    [AttributeChanged "Test"] = function(newValue)
        print("The attribute changed to", newValue) -- This will run when "Test" changes.
    end
}

I've also added some unit tests for attributes, however they might not be the greatest, so feel free to give any feedback for improvement!
Apologies if this PR isn't the best, I haven't done this before, however I'm open to any suggestions!

[krypt102]

Not sure why the unit tests didn't diff with an indent, not too much of a problem though.

[Dionysusnu]

Should there also be an AttributeOut feature as part of this, equivalent to the regular property Out functionality?

[krypt102]

Should there also be an AttributeOut feature as part of this, equivalent to the regular property Out functionality?

Actually not a bad idea, it's probably not best having the same issue as before when [Out] didn't exist where you'd need to connect change handlers to update state objects. Will implement!

[krypt102]

Passed all of my unit tests, not sure if anyone wants to add more but go ahead!

[dphfox]

Thanks for the PR! This won't be included in v0.2 since that's literally about to release, but I'll definitely look into including this alongside the rest of the instance changes planned for v0.3 :)

[krypt102]

Thanks for the PR! This won't be included in v0.2 since that's literally about to release, but I'll definitely look into including this alongside the rest of the instance changes planned for v0.3 :)

You're welcome! Hopefully it gets added in v0.3 provided that my code is up to standard 😃

[krypt102]

Gonna mark this as a draft for now until I sort out the indenting problems!

[krypt102]

Finally! I got the indents to work, I messed around with my VSC settings and stopped it from adding spaces, then went through the files and fixed it. If there's still problems please re-review, going to mark ready again.

[dphfox]

Alright, looks good to me. What do you guys think?

[krypt102]

Looks disgusting to me Nah I think I've put all the features that are necessary, we have [Attribute], [AttributeChange] and [AttributeOut], so it seems good for me!