Add Mermaid copy button, avoid unnecessary tooltip hide (#22225)

- Add Copy button to mermaid diagrams which copies their source.
- Set tippy to not hide on click and avoid tooltip re-creation for
temporary tooltips. This avoids hide and show when copying repo url.
Popovers still hide the tooltip as usual.


<img width="815" alt="Screenshot 2022-12-23 at 14 02 32"
src="https://user-images.githubusercontent.com/115237/209341696-98e30953-f246-46d9-9157-2ececfd791c9.png">

Co-authored-by: Lauris BH <lauris@nix.lv>
Co-authored-by: KN4CK3R <admin@oldschoolhack.me>

web_src/js/modules/tippy.js

@@ -6,6 +6,7 @@ export function createTippy(target, opts = {}) {
     placement: target.getAttribute('data-placement') || 'top-start',
     animation: false,
     allowHTML: false,
+    hideOnClick: false,
     interactiveBorder: 30,
     ignoreAttributes: true,
     maxWidth: 500, // increase over default 350px
@@ -46,7 +47,7 @@ export function showTemporaryTooltip(target, content) {
   }
 
   tippy.setContent(content);
-  tippy.show();
+  if (!tippy.state.isShown) tippy.show();
   tippy.setProps({
     onHidden: (tippy) => {
       if (oldContent) {