✨ 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/arknights/build.py

@@ -10,7 +10,7 @@ from nonebot_bison.theme.utils import web_embed_image
 from nonebot_bison.theme import Theme, ThemeRenderError, ThemeRenderUnsupportError
 
 if TYPE_CHECKING:
-    from nonebot_bison.post import Post
+    from nonebot_bison.platform.arknights import ArknightsPost
 
 
 @dataclass
@@ -32,7 +32,7 @@ class ArknightsTheme(Theme):
     template_path: Path = Path(__file__).parent / "templates"
     template_name: str = "announce.html.jinja"
 
-    async def render(self, post: "Post"):
+    async def render(self, post: "ArknightsPost"):
         from nonebot_plugin_htmlrender import template_to_pic
 
         if not post.title:
@@ -49,10 +49,9 @@ class ArknightsTheme(Theme):
                 raise ThemeRenderUnsupportError(
                     f"图片类型错误, 期望 str | Path | bytes | BytesIO | None, 实际为 {type(banner)}"
                 )
-
         ark_data = ArkData(
             announce_title=text_fletten(post.title),
-            content=post.content,
+            content=await post.get_content(),
             banner_image_url=banner,
         )