Fix inconsistent rendering of block mathematical expressions (#29677) (#29711)

Backport #29677 by @yp05327

Fix #28735

GitHub render `\```math\``` ` as a block now.
Add `display` class will render it as a block.

After:

![image](https://github.com/go-gitea/gitea/assets/18380374/2a1c20c7-438e-4ab1-8c66-cf91c8343087)

![image](https://github.com/go-gitea/gitea/assets/18380374/b81b8a93-8bca-46a5-b7db-e0d2f53e1342)

Co-authored-by: yp05327 <576951401@qq.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

diff --git a/modules/markup/markdown/markdown.go b/modules/markup/markdown/markdown.go
index 771162b9a3f126e5bd3543257aef3a31ce3cef7f..8bf3ac1da2e1f8ed999448b79ce48bca00800676 100644 (file)
--- a/modules/markup/markdown/markdown.go
+++ b/modules/markup/markdown/markdown.go
@@ -103,7 +103,8 @@ func SpecializedMarkdown() goldmark.Markdown {
                                                        }
 
                                                        // include language-x class as part of commonmark spec
-                                                       _, err = w.WriteString(`<code class="chroma language-` + string(language) + `">`)
+                                                       // the "display" class is used by "js/markup/math.js" to render the code element as a block
+                                                       _, err = w.WriteString(`<code class="chroma language-` + string(language) + ` display">`)
                                                        if err != nil {
                                                                return
                                                        }