Make position of #description configurable via the API for form field widgets

I just wanted to give you a heads up about a new project that solves this for D7: Form element layout. I would love to see a similar solution for D8. Unfortunately my work requires me to be in D7 land for quite some while, so I have no time to help in this issue.

Oh and yeah. Label help doesn't solve this. Quoting from its project page:

This module attempts to provide a more comprehensive, flexible and simpler-to-implement solution: a second help field that will appear directly below the form element's label.

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This module does not alter the positioning of the standard "description" field, so it is actually possible to have two separate pieces of "help" text for each form field -- one that appears directly below the label, and another that appears below the input form as it does now. (In practice, of course, most form fields will not need both.)

Dunno if it is related, but one of the biggest problem I had with Form element layout fields was that I had no idea how field widgets would structure their forms. So where the #description finally ended up (beeing rendered) wasn't possible to figure out programmatically, afaik. Maybe its easier in D8 now that field widgets have schema.

In multiple fields, the name of the field is output in the <thead> of a table. How could we inject the description if we want to show it before the actual fields, but after the title?

@alimac: The caption is shown before the table (and the h4), so I'm not sure if that is a potential solution.

<table id="body-values" class="field-multiple-table responsive-enabled tabledrag-processed tableresponsive-processed">
      <caption>Hello</caption>
      <thead>
      <tr>
                  <th colspan="2" class="field-label"><h4 class="label">Body</h4></th>
                  <th class="tabledrag-hide" style="display: none;">Order</th>
              </tr>
    </thead>
      <tbody>

I just opened #2371945: Move multivalue field's label out of rendered table to a separate <label> to provide HTML consistency that hopefully will move the label outside the table. Otherwise the help text will have to be rendered as a stand-alone table row after <thead> and before the input elements. But that again opens the question if it's the right thing to render the help text as a table row at the end of the table also if #description_display is set to after for multi value fields. The fact that the field's label is a part of the table is a really bad thing and IMHO borderline a bug.

Getting momentum on the above issue will help this issue a lot.

There's no patch to work on.

Let's bump this to 8.1.

Cleaning up drupalcampfi tags.

Since Label Help was mentioned in the issue description above, I thought I'd throw out that a Drupal 8 port has been created and along with the patch on #2948501: Improve Drupal 8 field compatibility, it is working nicely for a large number of field types, including multi-cardinality fields like those depicted in the screenshot of this issue's description above.

The Label Help module's D8 version tries to add the description to the #label_suffix, but since field-multiple-tables in Drupal 8 do not support #label_suffix, the patch on #2948501 simply appends the description to the #title so that it appears inside the <h4 class="label>.

While I'm not trying to change the purpose of this issue, it would be super slick if #label_suffix was just made to work with multi-cardinality fields.