Docs: Improve compatibility comment in `WP_List_Table`.

Improve comment explaining backward compatibility check for the primary column in `WP_List_Table::get_column_info()`.

Unprops helen, markjaquith.
See #52628, #34564.


Built from https://develop.svn.wordpress.org/trunk@50516


git-svn-id: http://core.svn.wordpress.org/trunk@50129 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/class-wp-list-table.php

@@ -1111,8 +1111,13 @@ class WP_List_Table {
 	protected function get_column_info() {
 		// $_column_headers is already set / cached.
 		if ( isset( $this->_column_headers ) && is_array( $this->_column_headers ) ) {
-			// Back-compat for list tables that have been manually setting $_column_headers for horse reasons.
-			// In 4.3, we added a fourth argument for primary column.
+			/*
+			 * Backward compatibility for `$_column_headers` format prior to WordPress 4.3.
+			 *
+			 * In WordPress 4.3 the primary column name was added as a forth item in the
+			 * column headers property. This ensures the primary column name is included
+			 * in plugins setting the property directly in the three item format.
+			 */
 			$column_headers = array( array(), array(), array(), $this->get_primary_column_name() );
 			foreach ( $this->_column_headers as $key => $value ) {
 				$column_headers[ $key ] = $value;

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.8-alpha-50512';
+$wp_version = '5.8-alpha-50516';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.