Coding Standards: Adjust coding standards to always omit parentheses for include/require statements.

These are language constructs, not function calls, so the parentheses are unnecessary.

This updates the PHPCS configuration file the enforce the sniff until it is moved from the `WordPress-Extra` ruleset to the `WordPress-Core` ruleset upstream.

Follow-up to [47198].

Props desrosj, jrf, GaryJ.
Fixes #49376.
Built from https://develop.svn.wordpress.org/trunk@47207


git-svn-id: http://core.svn.wordpress.org/trunk@47007 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/shortcodes.php

@@ -258,8 +258,7 @@ function get_shortcode_regex( $tagnames = null ) {
 	// Also, see shortcode_unautop() and shortcode.js.
 
 	// phpcs:disable Squiz.Strings.ConcatenationSpacing.PaddingFound -- don't remove regex indentation
-	return
-		'\\['                                // Opening bracket.
+	return '\\['                             // Opening bracket.
 		. '(\\[?)'                           // 1: Optional second opening bracket for escaping shortcodes: [[tag]].
 		. "($tagregexp)"                     // 2: Shortcode name.
 		. '(?![\\w-])'                       // Not followed by word character or hyphen.