Fix incorrect embeddings.md custom embedding example (#20143)

Update embeddings.md

Author: dowoncha

docs/src/content/docs/framework/module_guides/models/embeddings.md

@@ -349,25 +349,25 @@ class InstructorEmbeddings(BaseEmbedding):
         self._model = INSTRUCTOR(instructor_model_name)
         self._instruction = instruction
 
-        def _get_query_embedding(self, query: str) -> List[float]:
-            embeddings = self._model.encode([[self._instruction, query]])
-            return embeddings[0]
+    def _get_query_embedding(self, query: str) -> List[float]:
+        embeddings = self._model.encode([[self._instruction, query]])
+        return embeddings[0]
 
-        def _get_text_embedding(self, text: str) -> List[float]:
-            embeddings = self._model.encode([[self._instruction, text]])
-            return embeddings[0]
+    def _get_text_embedding(self, text: str) -> List[float]:
+        embeddings = self._model.encode([[self._instruction, text]])
+        return embeddings[0]
 
-        def _get_text_embeddings(self, texts: List[str]) -> List[List[float]]:
-            embeddings = self._model.encode(
-                [[self._instruction, text] for text in texts]
-            )
-            return embeddings
+    def _get_text_embeddings(self, texts: List[str]) -> List[List[float]]:
+        embeddings = self._model.encode(
+            [[self._instruction, text] for text in texts]
+        )
+        return embeddings
 
-        async def _get_query_embedding(self, query: str) -> List[float]:
-            return self._get_query_embedding(query)
+    async def _aget_query_embedding(self, query: str) -> List[float]:
+        return self._get_query_embedding(query)
 
-        async def _get_text_embedding(self, text: str) -> List[float]:
-            return self._get_text_embedding(text)
+    async def _aget_text_embedding(self, text: str) -> List[float]:
+        return self._get_text_embedding(text)
 ```
 
 ## Standalone Usage