Coding Standards: Use `KB_IN_BYTES` in `get_file_data()`.

See #22405, #47632.

git-svn-id: https://develop.svn.wordpress.org/trunk@45854 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/functions.php

@@ -5636,7 +5636,7 @@ function get_file_data( $file, $default_headers, $context = '' ) {
 	$fp = fopen( $file, 'r' );
 
 	// Pull only the first 8kiB of the file in.
-	$file_data = fread( $fp, 8192 );
+	$file_data = fread( $fp, 8 * KB_IN_BYTES );
 
 	// PHP will close file handle, but we are good citizens.
 	fclose( $fp );