Have `?` fall back to stringObj.

Note that ->forward is not used once an Object is in the environment.

src/env.c

@@ -410,6 +410,14 @@ Object help(Object* params, int length, struct Environment* env)
             return text;
         }
     }
+    Object* object = fetch(symbol, env);
+    if (object) {
+        size_t len;
+        char* string = stringObj(object, &len);
+        Object text = stringFromSlice(string, len);
+        free(string);
+        return text;
+    }
 
     return nullTerminated("Help not found!");
 }

src/object.h

@@ -106,7 +106,10 @@ struct Object {
 #endif
     };
 
-    Object* forward;
+    union {
+        Object* forward;
+        char* docString;
+    };
 };
 
 struct StructDef {