Support Admonitions in Markdown render

Describe the feature

Admonitions are supported in several Markdown renders like here in GitHub. It would be nice if Gogs supported it too.

The following tags are currently supported:

> [!NOTE]
> General information or additional context.

> [!TIP]
> A helpful suggestion or best practice.

> [!IMPORTANT]
> Key information that shouldn't be missed.

> [!WARNING]
> Critical information that highlights a potential risk.

> [!CAUTION]
> Information about potential issues that require caution.

And they are rendered this way:

[!NOTE]
General information or additional context.

[!TIP]
A helpful suggestion or best practice.

[!IMPORTANT]
Key information that shouldn't be missed.

[!WARNING]
Critical information that highlights a potential risk.

[!CAUTION]
Information about potential issues that require caution.

Describe the solution you'd like

I just want them to be displayed the same way on Gogs. Right now, they just appear as a blockquote, nothing more:

Sample

Describe alternatives you've considered

There are no magic solutions for this.

Additional context

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

No file or test is named in the issue. Start by locating Gogs's Markdown rendering entry point and related tests, then verify that the five listed tags render as admonitions rather than plain blockquotes.