Fix a typo (#818)

docs/api.md

@@ -355,7 +355,7 @@ curl -X POST http://localhost:11434/api/embeddings -d '{
 
 ```json
 {
-  "embeddings": [
+  "embedding": [
     0.5670403838157654, 0.009260174818336964, 0.23178744316101074, -0.2916173040866852, -0.8924556970596313,
     0.8785552978515625, -0.34576427936553955, 0.5742510557174683, -0.04222835972905159, -0.137906014919281
   ]