Why does `lowerCase`'s type signature is so general?

[KonradLinkowski]

Why does lowerCase's type signature looks like that:

function lowerCase(str: string): string;

When capitalize's looks like this:

function capitalize<T extends string>(str: T): Capitalize<T>;

Shouldn't it be:

function lowerCase<T extends string>(str: T): Lowercase<T>;

?

[raon0211]

I guess we should match capitalize if possible.