fix string_options code

Ooops, it was only half-implemented. Fixes eg.
`newFromFile("x.tif[page=2]");`.

Author: jcupitt

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 All notable changes to `:vips` will be documented in this file.
 
+## 2.0.2 - 2022-4-14
+
+- Fix extra optional string args on file open
+
 ## 2.0.1 - 2022-1-20
 
 - Fix library name on macOS [andrefelipe]

src/VipsOperation.php

@@ -320,6 +320,15 @@ public static function callBase(
                 "but $n_supplied supplied");
         }
 
+        /* set any string options before any args so they can't be
+         * overridden.
+         */
+        if (array_key_exists("string_options", $options)) {
+            $string_options = $options["string_options"];
+            unset($options["string_options"]);
+            $operation->setString($string_options);
+        }
+
         /* Set optional.
          */
         foreach ($options as $name => $value) {