Update supported rules

Supported-Markdown-syntaxes.md

@@ -7,23 +7,31 @@ In this page, you will learn all syntaxes you can use in your memo content.
 ## Supported markdown syntax
 
 If you are not familiar with markdown, please refer [Markdown Cheat Sheet](https://www.markdownguide.org/cheat-sheet/) to get started.
-We try to support all of these syntaxes.
-
-It is worth noting that the content after the horizontal rule will be hidden by default after the folding memo option is enabled.
+We try to support those useful syntaxes into memos.
 
 There are still some syntaxes that we don't support now.
 
-- [ ] Heading
-- [ ] Table (removed)
-- [ ] Footnote
-- [ ] Definition List
-- [ ] Emoji
-- [ ] Highlight
-- [ ] Subscript
-- [ ] Superscript
+### Basic Syntax
+
+- [x] Heading
+- [x] Bold
+- [x] Italic
+- [x] Blockquote
+- [x] Ordered List
+- [x] Unordered List
+- [x] Code
+- [x] Horizontal Rule
+- [x] Link
+- [x] Image
+
+### Extended Syntax
+
+- [x] Fenced Code Block
+- [x] Strikethrough
+- [x] Task List
 
 ## Something special
 
-1. Just like github's editor, you can directly write plain links
+1. Just like GitHub's editor, you can directly write plain links.
 1. `#` followed by text will be recognized as a tag, refer [Best practices to write a TAG](https://github.com/usememos/memos/wiki/Best-practices-to-write-a-TAG) to know more.
-1. **Unlike markdown**, you don't need to press `Enter` twice to break a line
+1. **Unlike markdown**, you don't need to press `Enter` twice to break a line.