Fix typings for using components as selectors.

[mgroenhoff]

What: Fix the typings to allow react components to be used as component selectors (fixes #685).

Why: Because when using Typescript 2.8.3 i get the following error:

Argument of type 'TemplateStringsArray' is not assignable to parameter of type 'CSSProperties | { [key: string]: ObjectStyleAttributes; } | ((props: ThemedProps<RowProps, Theme>...'.
Type 'TemplateStringsArray' is not assignable to type '(props: ThemedProps<RowProps, Theme>) => ObjectStyleAttributes'.
Type 'TemplateStringsArray' provides no match for the signature '(props: ThemedProps<RowProps, Theme>): ObjectStyleAttributes'.

How: I added a type to the list of allowed interpolation types.

Checklist:

• Documentation N/A
• Tests N/A
• Code complete N/A

Update: I changed it to only allow styled components and not regular (stateless) components.

[Ailrun]

@tkh44
It looks like this and #678 have some level of redundancy. Could you check it too?

[tkh44]

@Ailrun @mgroenhoff can you 2 coordinate on this? It looks like #678 can be applied on top of this but I'm not a TypeScript expert.

[Ailrun]

@mgroenhoff #678 is for remove redundancy between create-emotion-styled and react-emotion. Since we already have typings for create-emotion-styled, we don't need to add complex typings in react-emotion.

[mgroenhoff]

Okay, what do I need to change?

[Ailrun]

@mgroenhoff I mean... this PR is about changing the typings for react-emotion, and #678 is about removing typings (and replacing by typings from create-emotion-styled), so these intents make conflicts... don't they?

[mgroenhoff]

I think the idea behind #676 (which I missed) is the same as this PR. #678 indeed invalidates this one because it makes use of those changes. I'll have to test it out tomorrow morning but I think this will do the job too.

[mgroenhoff]

I have tested #678 and that solved my issue. Please merge that one 👍