feat(i18n): add i18n support for Markdown alert (#1269)

* docs: add blockquote with custom alert title

* feat: add alert types to i18n and update blockquote rendering

* fix: wrong translation key

* feat: add alert title translation for all supported languages

Done by AI

demo/content/post/Markdown Syntax/index.md

@@ -49,16 +49,19 @@ The blockquote element represents content that is quoted from another source, op
 
 ### Blockquote with alert
 
-> [!NOTE]  
+> [!NOTE]
 > Highlights information that users should take into account, even when skimming.
 
+> [!NOTE] Custom title
+> You can also provide a custom title for the note alert.
+
 > [!TIP]
 > Optional information to help a user be more successful.
 
-> [!IMPORTANT]  
+> [!IMPORTANT]
 > Crucial information necessary for users to succeed.
 
-> [!WARNING]  
+> [!WARNING]
 > Critical content demanding immediate user attention due to potential risks.
 
 > [!CAUTION]

demo/content/post/Markdown Syntax/index.zh.md

@@ -49,21 +49,24 @@ Itatur? Quiatae cullecum rem ent aut odis in re eossequodi nonsequ idebis ne sap
 
 ### 带提示的引用
 
-> [!NOTE]  
+> [!NOTE]
 > 突出显示用户在快速浏览时也应注意的信息。
 
 > [!TIP]
 > 可选信息，帮助用户更顺利地完成任务。
 
-> [!IMPORTANT]  
+> [!IMPORTANT]
 > 用户成功所必需的关键信息。
 
-> [!WARNING]  
+> [!WARNING]
 > 由于潜在风险而需要用户立即关注的关键内容。
 
 > [!CAUTION]
 > 某个操作可能带来的负面后果。
 
+> [!NOTE] 自定义标题
+> 如果你想使用自定义标题，可以在方括号后面添加标题文本，如上所示。
+
 ## 表格 (Tables)
 
 表格虽然不是 Markdown 核心规范的一部分，但 Hugo 出箱即用地支持它们。