revert white-space changes in docs (#12557)

### What problem does this PR solve?

Trailing white-spaces in commit 6814ace1aa
got automatically trimmed by code editor may causes documentation
typesetting broken.

Mostly for double spaces for soft line breaks.  

### Type of change

- [x] Documentation Update

docs/guides/chat/set_chat_variables.md

@@ -5,7 +5,6 @@ sidebar_custom_props: {
   categoryIcon: LucideVariable
 }
 ---
-
 # Set variables
 
 Set variables to be used together with the system prompt for your LLM.
@@ -94,7 +93,7 @@ from ragflow_sdk import RAGFlow
 rag_object = RAGFlow(api_key="<YOUR_API_KEY>", base_url="http://<YOUR_BASE_URL>:9380")
 assistant = rag_object.list_chats(name="Miss R")
 assistant = assistant[0]
-session = assistant.create_session()
+session = assistant.create_session()    
 
 print("\n==================== Miss R =====================\n")
 print("Hello. What can I do for you?")
@@ -102,9 +101,9 @@ print("Hello. What can I do for you?")
 while True:
     question = input("\n==================== User =====================\n> ")
     style = input("Please enter your preferred style (e.g., formal, informal, hilarious): ")
-
+    
     print("\n==================== Miss R =====================\n")
-
+    
     cont = ""
     for ans in session.ask(question, stream=True, style=style):
         print(ans.content[len(cont):], end='', flush=True)