Shiki languages to load besides angular-html, the language of playground code, and the languages it embeds. A language named like one of them replaces it, so register here the languages of shiki.langs in ng-doc.config.ts that playground code uses, for example a newer Angular template grammar.
Set the theme names in shiki.themes of ng-doc.config.ts instead, and load other themes with themes. This field will be removed in a future major release.
Has no effect, and is reported in development mode.
The theme names come from shiki.themes in ng-doc.config.ts: NgDoc highlights code blocks with them when it builds the site, and passes them to the application (NG_DOC_SHIKI_THEME), so the code that the browser highlights matches the code blocks.
