Use data-tooltip-content for tippy tooltip (#23649)

Follow:
* #23574
* Remove all ".tooltip[data-content=...]"

Major changes:

* Remove "tooltip" class, use "[data-tooltip-content=...]" instead of
".tooltip[data-content=...]"
* Remove legacy `data-position`, it's dead code since last Fomantic
Tooltip -> Tippy Tooltip refactoring
* Rename reaction attribute from `data-content` to
`data-reaction-content`
* Add comments for some `data-content`: `{{/* used by the form */}}`
* Remove empty "ui" class
* Use "text color" for SVG icons (a few)

web_src/js/features/comp/ReactionSelector.js

@@ -26,7 +26,7 @@ export function initCompReactionSelector(parent) {
       url,
       data: {
         _csrf: csrfToken,
-        content: $(this).data('content')
+        content: $(this).attr('data-reaction-content'),
       }
     }).done((resp) => {
       if (resp && (resp.html || resp.empty)) {