Add ZstdContext class stub

Author: thekid

zstd.stub.php

@@ -2,6 +2,8 @@
 
 namespace {
 
+  class ZstdContext {}
+
   function zstd_compress(string $data, int $level = 3): string|false {}
 
   function zstd_uncompress(string $data): string|false {}
@@ -22,6 +24,8 @@ function zstd_uncompress_add(ZstdContext $context, string $data): string|false {
 
 namespace Zstd {
 
+  class ZstdContext {}
+
   function compress(string $data, int $level = 3): string|false {}
 
   function uncompress(string $data): string|false {}