Fix types to work with new engine paths

manifest.json

@@ -1,7 +1,7 @@
 {
   "dev_7-3": {
     "description": "Development engine 7-3 for mathematical expression simplification.",
-    "type": "ruleset",
+    "type": "engine",
     "repo_id": "psaegert/simplipy-assets",
     "directory": "engines/dev_7-3",
     "files": [
@@ -12,7 +12,7 @@
   },
   "dev_7-2": {
     "description": "Development engine 7-2 for mathematical expression simplification.",
-    "type": "ruleset",
+    "type": "engine",
     "repo_id": "psaegert/simplipy-assets",
     "directory": "engines/dev_7-2",
     "files": [