Coding Standards: Use `self` when appropriate.

* `WP_List_Table::get_default_primary_column_name()` is a protected method, so calling it statically with the class name is bad practice.
* Similarly, this applies when calling a private constructor in `WP_Screen::get()`.

Props jrf.
See #50767.
Built from https://develop.svn.wordpress.org/trunk@49192


git-svn-id: http://core.svn.wordpress.org/trunk@48954 1a063a9b-81f0-0310-95a4-ce76da25c4cd

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

@@ -1073,7 +1073,7 @@ class WP_List_Table {
 		// If the primary column doesn't exist,
 		// fall back to the first non-checkbox column.
 		if ( ! isset( $columns[ $default ] ) ) {
-			$default = WP_List_Table::get_default_primary_column_name();
+			$default = self::get_default_primary_column_name();
 		}
 
 		/**

wp-admin/includes/class-wp-screen.php

@@ -377,7 +377,7 @@ final class WP_Screen {
 				return $screen;
 			}
 		} else {
-			$screen     = new WP_Screen();
+			$screen     = new self();
 			$screen->id = $id;
 		}
 

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.6-alpha-49190';
+$wp_version = '5.6-alpha-49192';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.