Add maxlength html attribute to textarea

Problem/Motivation

• Maxlength was not supported in older browsers prior to some version of the html spec
• It is now supported by Drupal Core Form API https://www.drupal.org/node/2887280 → and all modern browsers
• Can this module support adding the maxlength attribute to the form element in addition to the JS maxlength? Perhaps only if 'Enforce' is checked

Steps to reproduce

Set a maxlength on a textarea
Maxlength is applied via JS only, no maxlength attribute added to textarea input

Proposed resolution

Add maxlength to textarea when Enforce maximum length is set to true

Remaining tasks

• ❌Get maintainer approval for the proposed resolution
• ❌Implement resolution
• ❌Write test coverage (contact a maintainer if you need help)
• ❌Maintainer review via the UI
• ❌Maintainer Code Review #1
• ❌Maintainer code review #2
• ❌Merge into dev branch, with credit to author and participants

User interface changes

Browser maxlength will block input

API changes

None

Data model changes

None