[KYUUBI #6234] Fix invalid code-block syntax in docs

# 🔍 Description
## Issue References 🔗

This pull request fixes docs issue

## Describe Your Solution 🔧

Correct syntax

## Types of changes 🔖

- [x] Bugfix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing functionality to change)

## Test Plan 🧪

#### Behavior Without This Pull Request ⚰️

<img width="858" alt="image" src="https://github.com/apache/kyuubi/assets/26535726/66a74736-48d9-464d-b8cf-c3886aa1d125">

<img width="855" alt="image" src="https://github.com/apache/kyuubi/assets/26535726/fd6cd267-2fa6-493c-9976-61600ae427a0">

#### Behavior With This Pull Request 🎉

<img width="869" alt="image" src="https://github.com/apache/kyuubi/assets/26535726/adc7b7e0-29bf-4ba3-b96b-fddb14f6053a">

<img width="877" alt="image" src="https://github.com/apache/kyuubi/assets/26535726/1aac5c46-9064-4e34-95a0-16d64e7ef32e">

#### Related Unit Tests

---

# Checklist 📝

- [x] This patch was not authored or co-authored using [Generative Tooling](https://www.apache.org/legal/generative-tooling.html)

**Be nice. Be informative.**

Closes #6234 from pan3793/docs-fix.

Closes #6234

801b5d9 [Cheng Pan] Fix invalid code-block syntax in docs

Authored-by: Cheng Pan <[email protected]>
Signed-off-by: Cheng Pan <[email protected]>

docs/extensions/server/authentication.rst

@@ -72,7 +72,6 @@ To enable the custom authentication method, we need to
   on each node where kyuubi server is installed.
 
 .. code-block:: property
-   :margin:
 
    kyuubi.authentication=CUSTOM
    kyuubi.authentication.custom.class=YourAuthenticationProvider

docs/extensions/server/events.rst

@@ -74,7 +74,6 @@ To enable the custom EventHandler, we need to
   on each node where kyuubi server is installed. If you need use other event handler, it can be appended after the ``CUSTOM``.
 
 .. code-block:: property
-   :margin:
 
    kyuubi.backend.server.event.loggers=CUSTOM