Syntax lookup: function / uncurried function

[kevanstannard]

Suggestion for #162

• Add "function"
• Add "uncurried function"
• Remove old function_uncurried.mdx file.

[ryyppy]

I am still wondering if my proposal of putting () => {} and (.) => {} as a keyword is the right choice, but we are still able to change that if ppl find that confusing

[ryyppy]

Thanks for your work!