Add missing attributes for TextArea widget

[thomasmassmann]

The current widget lacks the following attributes:

• autocomplete
• autofocus
• maxlength
• minlength
• placeholder
• spellcheck
• wrap

The following attributes will be omitted:

• form: not required, as the field/widget is always placed inside a form

TextArea specification: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/textarea

When the maxlength attribute is set, a character counter should be visible below the field showing both the current amount of characters inserted and the maximum amount of characters allowed. An example implementation is available at https://htmldom.dev/count-the-number-of-characters-of-a-textarea/:

0/200

When the minlength attribute is set, a character counter should be visible as with the maximum counter, showing both the current amount of characters and the minimum amount of characters required, and an additional “required” hint (translated):

0/10 required

In case both minlength and maxlength attributes are set, only the maximum counter should be shown. The minimum character information should be placed in parentheses:

0/200 (10 required)

An example from Adam Silver’s book “Form Design Patterns”:

This version for the maxlength counter is more verbose, but should be taken only as an addition to the shortform (100/200):

You have 150 characters remaining (50/200).