Update Figlet implementation to be PHP8 compatible

Summary:
As of PHP ~v8 the `zip_open` and associated functions have been deprecated and
removed. The replacement is the `ZipArchive` API. This updates the figlet
implementation to use this API which has been present in PHP since 5.2.

Additionally in PHP 8 the use of squiggly brackets for indexing into arrays is
also deprecated. This updates to remove two uses of squiggly brackets and
replace with square brackets.

These two deprecations would result in being unable to load differential
revisions in which someone had commented using figlet remarkup.

Refs T13588

Test Plan:
Applied these changes to an install and loaded a revision that had comments
where someone utilized figlet remarkup. The revision loaded properly and the
figlet comment rendered properly.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: Korvin

Maniphest Tasks: T13588

Differential Revision: https://secure.phabricator.com/D21860

Author: neandrake

externals/pear-figlet/Text/Figlet.php

@@ -140,20 +140,15 @@ function loadFont($filename, $loadgerman = true)
         if (!$compressed) {
             /* ZIPed font */
             if (fread($fp, 2) == 'PK') {
-                if (!function_exists('zip_open')) {
-                    return self::raiseError('Cannot load ZIP compressed fonts since'
-                                            . ' ZIP PHP extension is not available.',
-                                            5);
-                }
-
                 fclose($fp);
-
-                if (!($fp = zip_open($filename))) {
-                    return self::raiseError('Cannot open figlet font file ' . $filename, 2);
+                $zip = new ZipArchive();
+                $open_result = $zip->open($filename, ZipArchive::RDONLY);
+                if ($open_result !== true) {
+                    return self::raiseError('Cannot open figlet font file ' .
+                        $filename . ', got error: ' . $open_result, 2);
                 }
-
-                $name = zip_entry_name(zip_read($fp));
-                zip_close($fp);
+                $name = zip->getNameIndex(0);
+                $zip->close();
 
                 if (!($fp = fopen('zip://' . realpath($filename) . '#' . $name, 'rb'))) {
                     return self::raiseError('Cannot open figlet font file ' . $filename, 2);
@@ -231,7 +226,7 @@ function loadFont($filename, $loadgerman = true)
                     $i = hexdec(substr($i, 2));
                 } else {
                     // If octal
-                    if ($i{0} === '0' && $i !== '0' || substr($i, 0, 2) == '-0') {
+                    if ($i[0] === '0' && $i !== '0' || substr($i, 0, 2) == '-0') {
                         $i = octdec($i);
                     }
                 }
@@ -274,7 +269,7 @@ function lineEcho($str, $inhtml = false)
                 $lt = hexdec(substr($str, $i+2, 4));
                 $i += 5;
             } else {
-                $lt = ord($str{$i});
+                $lt = ord($str[$i]);
             }
 
             $hb = preg_quote($this->hardblank, '/');
@@ -497,4 +492,4 @@ function _skip(&$fp)
   private static function raiseError($message, $code = 1) {
     throw new Exception($message);
   }
-}
+}