feat: support array validation

[icepeng]

This change includes some additional type info, and tests.

There are no changes in logic since value.length works same between string and array.

[MrWolfZ]

Thanks for this PR. From the code side there is absolutely nothing I think needs changing. What's missing is an update to the user guide, specifically the validation docs to mention the new capabilities.

[icepeng]

Ok. Is it possible to add commits in pull request? Or I have to open another one?

[MrWolfZ]

You can easily push other commits. Github mentions it right here:

"Add more commits by pushing to the array-validation branch on icepeng/ngrx-forms."

[MrWolfZ]

Alright, then one last thing: please target the develop branch instead of master with this PR.

[icepeng]

Ah, it works well. Since I am not friendly at English (I'm living in Korea) - there would be some grammar errors.

[icepeng]

Ohh. Fixed target branch.

[MrWolfZ]

No worries, there are no grammar errors or typos I could spot.

I just noticed one more thing though: The inline documentation for the validation functions also needs to be adjusted, e.g. this line needs to mention arrays now as well (same for other functions).

[icepeng]

Updated, it would be better to merge last two commits.

[MrWolfZ]

Merging the commits is not required in my opinion. However, you are of course free to do so if you want.

I'll be away now for about 2 hours. Afterwards I'll merge the PR.

[icepeng]

Thank you for great support.