Tabpane: improve key-kind default setting

[chalin]

• Contributes to Tabpane shortcode fixes and enhancements (23Q3-Q4) #1641
• Improves the default setting of the tabpane key kind, now handling cases were text=true
• Refactors tab.html slightly, by making use of . instead of repeating the with expression
• Preview: https://deploy-preview-1643--docsydocs.netlify.app/docs/adding-content/shortcodes/#tabbed-panes

---

The only change in the generated UG is that the Welcome! tabbed panes are now persisted using the tab header as a key rather than the language:

$ (cd userguide/public && git diff -I "data-td-tp-persist=\"(en|de|ge|sw)" -- . ':(exclude)*.xml') | grep ^diff
# No change
$ (cd userguide/public && git diff -- . ':(exclude)*.xml') | grep ^diff 
diff --git a/docs/_print/index.html b/docs/_print/index.html
diff --git a/docs/adding-content/_print/index.html b/docs/adding-content/_print/index.html
diff --git a/docs/adding-content/shortcodes/index.html b/docs/adding-content/shortcodes/index.html
$ (cd userguide/public && git diff -- . ':(exclude)*.xml') | head      
...

diff --git a/docs/_print/index.html b/docs/_print/index.html
index 29d8bb8..d250b65 100644
--- a/docs/_print/index.html
+++ b/docs/_print/index.html
@@ -5396,19 +5396,19 @@ in the response headers.&rdquo; you <strong>CAN</strong> embed it, but when the
     </li><li class="nav-item">
       <button class="nav-link active"
           id="tabs-08-01-tab" data-bs-toggle="tab" data-bs-target="#tabs-08-01" role="tab"
-          data-td-tp-persist="en" aria-controls="tabs-08-01" aria-selected="true">
+          data-td-tp-persist="english" aria-controls="tabs-08-01" aria-selected="true">

[deining]

LGTM