Add mermaid and math examples

rendering_test.md

@@ -3,8 +3,7 @@
 This file tests Gitea's ability to render various Markdown elements.
 
 ## 1. Text Formatting
-*Italic*, **Bold**, ***Bold Italic***, ~~Strikethrough~~, Inline Code
+*Italic*, **Bold**, ***Bold Italic***, ~~Strikethrough~~, \Inline Code
-
 ## 2. Lists
 ### Unordered
 - Item 1
@@ -54,6 +53,30 @@ def hello_world():
 
 ![Gitea Logo](https://gitea.io/images/gitea.png)
 
-## 7. Mathematical Formulas (if enabled)
+## 7. Mathematical Formulas
+Display Math:
 d:\Project\GitBasedDevelopmentEnvironmentSetup \sqrt{3x-1}+(1+x)^2 d:\Project\GitBasedDevelopmentEnvironmentSetup
 
+Inline Math: \=mc^2$
+
+## 8. Mermaid Diagrams
+\\mermaid
+sequenceDiagram
+ participant Alice
+ participant Bob
+ Alice->>John: Hello John, how are you?
+ loop Healthcheck
+ John->>John: Fight against hypochondria
+ end
+ Note right of John: Rational thoughts <br/>prevail!
+ John-->>Alice: Great!
+ John->>Bob: How about you?
+ Bob-->>John: Jolly good!
+\
+\\mermaid
+graph TD
+ A[Start] --> B{Is it working?};
+ B -- Yes --> C[Great!];
+ B -- No --> D[Debug];
+ D --> B;
+\EOF