Replace theme() with drupal_render() in tablesort.inc

Patch attached.

After pondering the doc changes for a while, I'm ok with these changes, could use a second opinion from the doc master @Cottser. But RTBC from me.

+++ b/core/includes/tablesort.inc
@@ -9,7 +9,7 @@
- * All tables created with a call to theme('table') have the option of having
+ * All tables created with a call to drupal_render() have the option of having

I would sooner change instances of theme('table') and theme_table to '#theme' => 'table', that applies to all the doc changes here.

+++ b/core/includes/tablesort.inc
@@ -9,7 +9,7 @@
+ * All tables created with a call to '#theme' => 'table' have the option of having

80 col rule violation?

trivial coding standard quickfix

Maybe this will read better if reads "with a call to" changed to "when rendering a"

Updated comments only.

My IDE reports that many of the use statements in this file are unused and that

use Drupal\Core\Database\Connection;
use Drupal\Core\Database\Query\SelectExtender;
use Drupal\Core\Database\Query\SelectInterface;
use Drupal\Component\Utility\Url;

could be reduced to

use Drupal\Component\Utility\Url;

is that beyond the scope of this issue?

@martin107 - yep, definitely out of scope here.

Opened #2189729: Factor out tablesort-indicator.html.twig as a follow-up. Patch here looks fine - will try to remember to get it next time I'm committing stuff.

Committed/pushed to 8.x, thanks!