Separate reference docs into different block (#180)

## Purpose
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does it solve or functionality does it add? -->
* ...
#175 
## Does this introduce a breaking change?
<!-- Mark one with an "x". -->
```
[ ] Yes
[ ] No
```

## Pull Request Type
What kind of change does this Pull Request introduce?

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```
[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Documentation content changes
[ ] Other... Please describe:
```

## How to Test
*  Get the code

```
git clone [repo-address]
cd [repo-name]
git checkout [branch-name]
npm install
```

* Test the code
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```
```

## What to Check
Verify that the following are valid
* ...

## Other Information
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Author: LittleLittleCloud

app/backend/Services/ReadRetrieveReadChatService.cs

@@ -112,7 +112,7 @@ standard plan AND dental AND employee benefit.
 
 You answer needs to be a json object with the following format.
 {{
-    ""answer"": // the answer to the question, add a source reference to the end of each sentence. e.g. Apple is a fruit [reference1.pdf]. If no source available, put the answer as I don't know.
+    ""answer"": // the answer to the question, add a source reference to the end of each sentence. e.g. Apple is a fruit [reference1.pdf][reference2.pdf]. If no source available, put the answer as I don't know.
     ""thoughts"": // brief thoughts on how you came up with the answer, e.g. what sources you used, what you thought about, etc.
 }}");