Add copy button to markdown code blocks (#17638)

* Add copy button to markdown code blocks

Done mostly in JS because I think it's better not to try getting buttons
past the markup sanitizer.

* add svg module tests

* fix sanitizer regexp

* remove outdated comment

* vertically center button in issue comments as well

* add comment to css

* fix undefined on view file line copy

* combine animation less files

* Update modules/markup/markdown/markdown.go

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

* add test for different sizes

* add cloneNode and add tests for it

* use deep clone

* remove useless optional chaining

* remove the svg node cache

* unify clipboard copy string and i18n

* remove unused var

* remove unused localization

* minor css tweaks to the button

* comment tweak

* remove useless attribute

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

1 files changed, 3 insertions, 2 deletions

diff --git a/web_src/js/markup/mermaid.js b/web_src/js/markup/mermaid.js
index f9f069ed1e..7c7ee26c3c 100644
--- a/web_src/js/markup/mermaid.js
+++ b/web_src/js/markup/mermaid.js
@@ -8,8 +8,9 @@ function displayError(el, err) {
   el.closest('pre').before(errorNode);
 }
 
-export async function renderMermaid(els) {
-  if (!els || !els.length) return;
+export async function renderMermaid() {
+  const els = document.querySelectorAll('.markup code.language-mermaid');
+  if (!els.length) return;
 
   const {default: mermaid} = await import(/* webpackChunkName: "mermaid" */'mermaid');