Fix to-be-disabled reaction on disabled="false"

[JakubGIT]

What:

• fix the .toBeDisabled() treatment of a button with attribute and value `disabled='false', which happens by web-components, see expect().toBeEnabled() fails by disabled="false" #489

Why:

• expect().toBeEnabled() fails by disabled="false" #489
• web-component buttons with dynamically changing disabled attribute were not evaluated correctly

How:

• by adding an additional check element.attributes.disabled.value !== 'false'

Checklist:

• Documentation N/A
• Tests
• Updated Type Definitions N/A
• Ready to be merged
  

[pseudogram]

I was going to give this a +1 then I read the docs for the HTML attribute 'disabled'.

A note for those to come:

If you are writing semantic HTML you should not add the attribute disabled if a button is enabled. And there is no such thing as disabled="false" because the attribute has no value.

Reading the double negative probably makes you think, "Something's up?" 🤔

In JSX you should be passing a boolean value to the disabled attribute (not a string). React will handle it the boolean and render the attribute accordingly.