feat: html in readme #30

On GitHub, you can use HTML which is quite nice, especially for things like spoilers; It should be fairly trivial to add HTML support as far as I'm aware. If I'm not missing something major, I believe /appview/pages/markdown.go just needs to have the goldmark HTML renderer in unsafe mode passed into the bluemonday sanitizer (which is already a dependency of this repo). I would have opened a PR but not entirely sure the proper etiquette to do that with just branches :)

diff --git a/appview/pages/markdown.go b/appview/pages/markdown.go
index d27d906..4e92a0d 100644
--- a/appview/pages/markdown.go
+++ b/appview/pages/markdown.go
@@ -3,21 +3,44 @@ package pages
 import (
        "bytes"

+       "github.com/microcosm-cc/bluemonday"
        "github.com/yuin/goldmark"
        "github.com/yuin/goldmark/extension"
        "github.com/yuin/goldmark/parser"
+       "github.com/yuin/goldmark/renderer/html"
 )

 func renderMarkdown(source string) string {
+       // Configure goldmark to allow raw HTML
        md := goldmark.New(
                goldmark.WithExtensions(extension.GFM),
                goldmark.WithParserOptions(
                        parser.WithAutoHeadingID(),
                ),
+               goldmark.WithRendererOptions(
+                       html.WithHardWraps(),
+                       html.WithUnsafe(), // Allow raw HTML to pass through
+               ),
        )
+
+       // Convert markdown to HTML
        var buf bytes.Buffer
        if err := md.Convert([]byte(source), &buf); err != nil {
                return source
        }
-       return buf.String()
+
+       // Create a policy that allows common HTML elements and attributes
+       policy := bluemonday.UGCPolicy()
+       // You can customize the policy to allow specific tags and attributes
+       policy.AllowElements("div", "span", "p", "br", "hr", "h1", "h2", "h3", "h4", "h5", "h6")
+       policy.AllowElements("ul", "ol", "li")
+       policy.AllowElements("table", "thead", "tbody", "tr", "th", "td")
+       policy.AllowElements("a", "img")
+       policy.AllowAttrs("href").OnElements("a")
+       policy.AllowAttrs("src", "alt").OnElements("img")
+       policy.AllowAttrs("class").Globally()
+
+       // Sanitize the HTML
+       sanitized := policy.Sanitize(buf.String())
+       return sanitized
 }