Update README

Signed-off-by: Jael Gu <mengjia.gu@zilliz.com>

README.md

@@ -2,7 +2,7 @@
 
 *author: Jael Gu*
 
-
+<br />
 
 ## Desription
 
@@ -17,6 +17,8 @@ The original model was proposed in REALM: Retrieval-Augmented Language Model Pre
 
 [2].https://arxiv.org/abs/2002.08909
 
+<br />
+
 ## Code Example
 
 Use the pretrained model "google/realm-cc-news-pretrained-embedder"
@@ -33,6 +35,8 @@ dc.stream(["Hello, world."]) \
   .to_list()
 ```
 
+<br />
+
 ## Factory Constructor
 
 Create the operator via the following factory method
@@ -41,11 +45,12 @@ Create the operator via the following factory method
 
 **Parameters:**
 
-​	***model_name***: *str*
+***model_name***: *str*
 
-​	The model name in string.
+The model name in string.
 You can get the list of supported model names by calling `get_model_list` from [realm.py](https://towhee.io/text-embedding/realm/src/branch/main/realm.py).
 
+<br />
 
 ## Interface
 
@@ -56,9 +61,9 @@ and then return text embedding in ndarray.
 
 **Parameters:**
 
-​	***text***: *str*
+***text***: *str*
 
-​	The text in string.
+The text in string.