Create a standard "help" element

[quicksketch]

In dozens of places throughout core we have a pattern of creating a "help" element with the following code:

$form['help'] = array(
  '#markup' => '<p>' . t('Help text') . '</p>',
);

We should create a standard element so that help text is displayed consistently. e.g.

$form['help'] = array(
  '#type' => 'help',
  '#markup' => t('Help text'),
);

This would allow themers to override theme_help() if needed, and we could standardize whether a <p> tag is added or not.

---

PR backdrop/backdrop#1794

[quicksketch]

The PR at backdrop/backdrop#1794 adds the following:

• Adds a help element as described above, and replaces all the locations where we had added $form['help'] in a form structure.
• Creates markup such as:

<div class="help"><p>The help text.</p></div>

• <p> tags are automatically added if missing. But allow for them to be present with #markup if the help text needs multiple paragraphs of explanation.

[klonos]

Seems a simple change to me and it is backwards compatible as in if someone still uses the "old", #markup way, things will still work. 👍

[quicksketch]

Great thanks for the review @klonos! Merged backdrop/backdrop#1794 into 1.x for 1.7.0.

[klonos]

Shouldn't https://api.backdropcms.org/form_api be updated to include this?

[jenlampton]

I've updated the Form API docs at https://api.backdropcms.org/form_api#help. Can someone confirm that #attriubutes will work? I think I got everything else.

edit: I checked the PR and it looks like #attributes will not work, so I've removed that X from the grid. Closing this issue :)