Description

This feature requires updating any css targeting the .choices [hidden] selector

This PR adds visual feedback on required fields by adding the class is-invalid on the invalid event (only when the input or select are required). Within a change, it will check again if our value is valid, thus removing the class.

I have updated the documentation accordingly and added a test-case and an update on the index.html (commented it out in fdf07fa and 83d2b0a as I sadly can't update the screenshots 😢). /cc @Xon 😊

This fixes, supersedes and implements:

• No workaroud validation when select is required #1148
• Required Must Select #1070
• Required validation not working for me #1061
• Breaking Bootstrap HTML5 validation (on submit) #1022
• Allow choices to decorate an invalid field #1020
• Required attribute not working on select field #1007

Screenshots (if appropriate)

Types of changes

• Chore (tooling change or documentation change)
• Refactor (non-breaking change which maintains existing functionality)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

• My code follows the code style of this project.
• I have added new tests for the bug I fixed/the new feature I added.
• I have modified existing tests for the bug I fixed/the new feature I added.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.