The following keys are a little misleading and I would like to rename them before SkinMustache is considered stable and sees more usage.
# acceptance criteria
[] html-headelement is removed from the array of data and appended directly in generateHTML
[] html-printtail is removed from the array of data and appended directly in generateHTML
[] html-bodycontent is renamed html-page-body to reflect that it is the body of the article.
[] html-printfooter in all wikimedia skins comes after html-bodycontent so as a result it will be merged into html-body-content/html-page-body so that it becomes non-optional and removed from the array of data
[] html-catlinks is renamed html-categories to be more descriptive.
[] A comment exists informing developers of the naming criteria and that words must exist in Wiktionary e.g. https://en.wiktionary.org/wiki/sitenotice vs https://en.wiktionary.org/wiki/subtitle
## For completeness
In https://gerrit.wikimedia.org/r/c/mediawiki/core/+/610294 several variables were introduced. In a follow up these will be renamed as follows:
[] updating data-aftercontent to data-after-content
[] html-userlangattributes to html-user-language-attributes
[]Update html-sitenotice to html-notices
= Developer notes
Desired end result regarding html-headelement and html-printtail:
```
return $out->headElement( $this ) . $templateParser->processTemplate(
$this->options['template'] ?? 'skin',
$this->getTemplateData()
) . WrappedStringList::join( "\n", $tail );
```