Files/IncludingFile: allow for more path-returning functions

As per the thread in 740, these functions all return the full path to a file, so these should all be fine.
As things were, use of these in an `include`/`require` statement would throw an unjustified "Absolute include path must be used" warning.

Includes a few extra tests, though I didn't think it would be necessary to have tests with each of these functions.

Fixes 740

WordPressVIPMinimum/Sniffs/Files/IncludingFileSniff.php

@@ -26,10 +26,30 @@ class IncludingFileSniff extends AbstractFunctionRestrictionsSniff {
 	 */
 	public $getPathFunctions = [
 		'dirname',
+		'get_404_template',
+		'get_archive_template',
+		'get_attachment_template',
+		'get_author_template',
+		'get_category_template',
+		'get_date_template',
+		'get_embed_template',
+		'get_front_page_template',
+		'get_page_template',
+		'get_paged_template', // Deprecated, but should still be accepted for the purpose of this sniff.
+		'get_home_template',
+		'get_index_template',
 		'get_parent_theme_file_path',
+		'get_privacy_policy_template',
+		'get_query_template',
+		'get_search_template',
+		'get_single_template',
+		'get_singular_template',
 		'get_stylesheet_directory',
+		'get_tag_template',
+		'get_taxonomy_template',
 		'get_template_directory',
 		'get_theme_file_path',
+		'locate_block_template',
 		'locate_template',
 		'plugin_dir_path',
 	];

WordPressVIPMinimum/Tests/Files/IncludingFileUnitTest.inc

@@ -34,4 +34,9 @@ include_once   dir_function(); // Error - custom functionm with keyword from $al
 require CUSTOM_CONSTANT_DIR . 'file.php'; // OK.
 require_once ( VIPCS_PATH ) . 'file.php'; // OK.
 include_once      
-  DIR_CUSTOM , 'file.php'; // OK.
+  DIR_CUSTOM , 'file.php'; // OK.
+
+// These are valid (previously false positives).
+include( get_404_template() );
+require get_query_template( 'post' );
+include_once locate_block_template( __DIR__, 'silly_block' );