feat: add deprecation meta

[hellerve]

This PR adds the meta form deprecated. It will be rendered in HTML (see the screenshot below) and in the REPL, like so:

> :i =>
=> : Macro
  Defined at line 27, column 3 in '/Users/veitheller/Documents/Code/Github/carp/carp/core/ControlMacros.carp'
  Deprecated: true

Cheers

[jacereda]

I would prefer "Deprecated" instead of "Deprecated: true", I guess that's also a problem now for hidden and friends.

[TimDeve]

I would make an explanation of the deprecation mandatory, personally.

[hellerve]

I would prefer "Deprecated" instead of "Deprecated: true", I guess that's also a problem now for hidden and friends.

I agree! I went the extra mile and fixed this for all the boolean values we work with.

[hellerve]

I would make an explanation of the deprecation mandatory, personally.

What would go in the explanation? What to use instead? Why it was deprecated?

[TimDeve]

Yeah, I feel that a deprecated note without any guidance is not very useful to the end user.

[eriksvedang]

Maybe any non-nil value means it's deprecated. Would enable this:

Deprecated: Replaced by ->

[hellerve]

deprecated now receives an optional string argument that will be rendered if it is provided.

This code was used to generated the above:

(deprecated example)
(defn example [] 1)

(deprecated another-example "was deprecated in favor of nothing. Have fun!")
(defn another-example [] 1)

I think this is the best compromise.

[eriksvedang]

Looks great, thanks for pleasing us all!

[eriksvedang]

Huh, I thought I merged this (sorry for dragging my feet). Has conflicts now, will merge when fixed.

[hellerve]

Fixed.