fix: wrong type for StoreFunction of helper

[Mufanc]

What does it do?

The require actually leads to the imported type becoming any, which will cause some return value of helpers that actually return boolean or complex types to be incorrectly threated as string, yet cannot be detected by eslint, for example here:

hexo/lib/plugins/helper/index.ts

Lines 31 to 41 in 492debf

	const is = require('./is');
	helper.register('is_current', is.current);
	helper.register('is_home', is.home);
	helper.register('is_home_first_page', is.home_first_page);
	helper.register('is_post', is.post);
	helper.register('is_page', is.page);
	helper.register('is_archive', is.archive);
	helper.register('is_year', is.year);
	helper.register('is_month', is.month);
	helper.register('is_category', is.category);
	helper.register('is_tag', is.tag);

and here:

hexo/lib/plugins/helper/index.ts

Lines 69 to 71 in 492debf

	const tagcloud = require('./tagcloud');
	helper.register('tagcloud', tagcloud);
	helper.register('tag_cloud', tagcloud);

And this might lead to some undefined behaviors, so I think the return type of StoreFunction in the helper should be changed to any.

Screenshots

Pull request tasks

• Add test cases for the changes.
• Passed the CI test.

[github-actions]

How to test

git clone -b refactor-types https://github.com/Mufanc/hexo.git
cd hexo
npm install
npm test