Fix error message for calling record macro with kwargs

[a-alhusaini]

Thanks to straight-shoota, hertdevil, blacksmoke, and devonte's thoughts and ideas we now get this error message when a named arg is provided to record

Error: Cat does not accept named arguments

    You probably wrote:

      record Cat, name: String

    instead of:

      record Cat, name : String

The error is a bit long but I believe it is better than just telling the user that record does not accept named arguments. The space costs are more than made up for by the clarity of the message.

[HertzDevil]

The trailing whitespace will still show up:

Suggested change

	record #{name}, #{(properties + kwargs.map{|name, value| "#{name} : #{value}"}).join(", ").id}
	" unless kwargs.empty? %}
	record #{name}, #{(properties + kwargs.map { |name, value| "#{name} : #{value}" }).join(", ").id}" unless kwargs.empty? %}

[HertzDevil]

This is not unique to this PR, but I wonder why the compiler inserts a newline right after the first line of the error message itself

[a-alhusaini]

This current solution does not work with Strings. I am not sure why.
I tried
record Cat, name: String
This shows undefined constant
record Cat, name: Int64
This shows the error we want.

Any ideas?

[Blacksmoke16]

@a-alhusaini FWIW both of those examples produce an undefined constant error. I imagine it's just because name an actual parameter on the record macro so it's not actually being captured in kwargs.

[HertzDevil]

Such an argument mismatch will always be possible as long as there is a positional parameter for the record's name, and Crystal does not have purely positional parameters. There are 2 possible solutions: (the second is probably better here)

# uglier, but ensures no mismatch can ever happen
macro record(*name_and_properties, **kwargs)
  {% name = name_and_properties[0] %}
  {% properties = name_and_properties[1...name_and_properties.size] %}
end

# names containing `__` are reserved by Crystal, so technically
# no user code should ever use a named argument for `__name`
macro record(__name name, *properties, **kwargs)
end