[8.x] Add complimentary Str::doesntContain

[jasonmccreary]

Similar to the recent additions to the Collection class, this PR adds a complimentary doesntContain method. This may be used to test a string does not contain a substring or set of substrings, which allow the developer to write more expressive code.

Before

if (! Str::contains('foo', 'bar')) {
    // ...
}

if (! Str::containsAll('foo', ['bar', 'baz'])) {
    // ...
}

After

if (Str::doesntContain('foo', 'bar')) {
    // ...
}

if (Str::doesntContain('foo', ['bar', 'baz'])) {
    // ...
}

[foremtehan]

Can you also add those to Stringable class ? https://github.com/laravel/framework/blob/8.x/src/Illuminate/Support/Stringable.php

[jasonmccreary]

@foremtehan, you got it.

[taylorotwell]

Going to hold off on this for now - mainly because the wording around it confuses my brain when I start thinking about possible methods for a method that would determine if a string doesn't contain at least one of the given strings.

[jasonmccreary]

No problem. Negated methods can be rather mind bending. Especially with parameter overloading like this one.

I really only chose this name because you used it for the same method on the Collection class. I'd probably have called it missing, doesntContainAny, or doesntInclude.