✨ 实现 Post.content 相关扩展协议 (#553)

* ✨ `post` 新增 `get_content()` 方法

* 🚨 make linter happy

* 💄 auto fix by pre-commit hooks

* 🐛 fix: 调整函数使用

* 💄 auto fix by pre-commit hooks

* ✨ 转用函数处理文本

* 💄 auto fix by pre-commit hooks

* 🔨 使用`Dict`存储`content_handlers`

* 💄 auto fix by pre-commit hooks

* 🎨 fix

* :arts: 简化函数使用

* 🐛 移除`Theme`的过时参数

* 🗑️ 复用 `self.plain_content`

* 💄 auto fix by pre-commit hooks

* ✨ 注册式装饰器写法

* 💄 auto fix by pre-commit hooks

* 🐛 fix

* 💄 auto fix by pre-commit hooks

* :feat: 通用纯文本处理函数

* 💄 auto fix by pre-commit hooks

* :downgrade: 复用`==`处理标题

* 🎨 简化（？）写法

* ✅ 测试修复

* ♻️ via ContentSupport extensions

* 🐛 fix test

* 💄 auto fix by pre-commit hooks

* 🐛 for clean text

* 🐛 fix

* 💄 auto fix by pre-commit hooks

* fix: for xml

* 💄 auto fix by pre-commit hooks

* chore: art

* 💄 auto fix by pre-commit hooks

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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

nonebot_bison/theme/themes/ceobe_canteen/build.py

@@ -95,7 +95,7 @@ class CeobeCanteenTheme(Theme):
         if post.images:
             images = await self.merge_pics(post.images, http_client)
 
-        content = CeoboContent(text=post.content)
+        content = CeoboContent(text=await post.get_content())
 
         retweet: CeoboRetweet | None = None
         if post.repost:
@@ -106,7 +106,9 @@ class CeobeCanteenTheme(Theme):
                 images.extend(repost_images)
 
             repost_nickname = f"@{post.repost.nickname}:" if post.repost.nickname else ""
-            retweet = CeoboRetweet(image=repost_head_pic, content=post.repost.content, author=repost_nickname)
+            retweet = CeoboRetweet(
+                image=repost_head_pic, content=await post.repost.get_content(), author=repost_nickname
+            )
 
         return (
             CeobeCard(