add headline block to block templates

[fritzmg]

It frequently happens that users want to change the headline part of specific module or content element templates. Currently, if you want to change that part of the template, you have to ditch the template extension and simply copy over the complete block_… template to your target template (while preserving the original content block in the target template).

Wouldn't it be better if, for instance, the block_unsearchable template was set up like this:

<!-- indexer::stop -->
<div class="<?= $this->class ?> block"<?= $this->cssID ?><?php if ($this->style): ?> style="<?= $this->style ?>"<?php endif; ?>>

  <?php $this->block('headline'); ?>
    <?php if ($this->headline): ?>
      <<?= $this->hl ?>><?= $this->headline ?></<?= $this->hl ?>>
    <?php endif; ?>
  <?php $this->endblock(); ?>

  <?php $this->block('content'); ?>
  <?php $this->endblock(); ?>

</div>
<!-- indexer::continue -->

This way you could do the follwing in, let's say, a mod_newsarchive template:

<?php $this->extend('block_unsearchable'); ?>

<?php $this->block('headline'); ?>
  <h1>My custom headline</h1>
<?php $this->endblock(); ?>

<?php $this->block('content'); ?>

  <?php if (empty($this->articles)): ?>
    <p class="empty"><?= $this->empty ?></p>
  <?php else: ?>
    <?= implode('', $this->articles) ?>
    <?= $this->pagination ?>
  <?php endif; ?>

<?php $this->endblock(); ?>

And thus preserving at least the wrapper of the original block_… template - instead of having to copy over the rest of the block_unsearchable template like this:

<!-- indexer::stop -->
<div class="<?= $this->class ?> block"<?= $this->cssID ?><?php if ($this->style): ?> style="<?= $this->style ?>"<?php endif; ?>>

  <h1>My custom headline</h1>

  <?php if (empty($this->articles)): ?>
    <p class="empty"><?= $this->empty ?></p>
  <?php else: ?>
    <?= implode('', $this->articles) ?>
    <?= $this->pagination ?>
  <?php endif; ?>

</div>
<!-- indexer::continue -->

[fritzmg]

Implemented in contao/core-bundle#457