Improved SCSS for revealjs - part 1

[cderv]

This PR does various improvement

• Refactor some SCSS code for better understanding what it is doing
• Move definition and variables in different places to group with other related rules
• Fixes Regression in font size for inline code present in callout blocks in Revealjs format #11215 so that new $code-block-font-size and $code-inline-font-size from brand brand,fonts,bootstrap - add support for weight+size+color customization #11028 correctly works with smaller size content (like callouts and .smaller class
  • It also exports them as CSS var --r-inline-code-font-size and --r-block-code-font-size, to complement --r-inline-code-font and --r-block-code-font. This is useful for testing too.
  • Remove $inlineCodeFont and $blockCodeFont which are intermediates not in settings.scss from revealjs. This part of the file is for variables from revealjs itself (for themes).
• New revealjs specific variable $revealjs-code-inline-font-size and $revealjs-code-block-font-size to match other $revealjs-* export (at

  quarto-cli/src/resources/formats/revealjs/quarto.scss

  Line 122 in 570fb44

  // --- derive reveal versions of presentation variables for finer-grained override ---

  )
• It also adds some playwright test to compute font-size and check this is what we expect. This should help detect in advanced problem like Regression in font size for inline code present in callout blocks in Revealjs format #11215

It seems a lot of changes, but it is only some reorganization to help fix issues like #5832 and other on callout (which are coming next)