Log Message:
(www/R-bslib) Updated 0.8.0 to 0.9.0

# bslib 0.9.0

## Breaking changes

* The navbar-related style options of `page_navbar()` and
  `navset_bar()` have been consolidated into a single `navbar_options`
  argument that pairs with a new `navbar_options()` helper. Using the
  direct `position`, `bg`, `inverse`, `collapsible`, and `underline`
  arguments will continue to work with a deprecation message. (#1141)

  Related to the above change, `navset_bar()` now defaults to using
  `underline = TRUE` so that both `page_navbar()` and `navset_bar()`
  use the same set of default `navbar_options()`.

  In `navbar_options()`, `inverse` is replaced by `theme`, which
  takes values `"light"` (dark text on a **light** background),
  `"dark"` (light text on a **dark** background), or \ 
`"auto"` (follow
  page settings, the default). This change affects that default
  navbar foreground and background colors for Bootswatch preset
  themes with Bootstrap 5. Detailed instructions for customizing the
  navbar appearance, especially for Bootswatch themes, can be found
  in `?navbar_options`. (#1146)

## New features

* bslib now supports unified theming with
  [brand.yml](https://posit-dev.github.io/brand-yml/). brand.yml lets
  you theme your Shiny apps, Quarto documents and more with a single,
  portable YAML file. Learn more in the new [Unified theming with
  brand.yml](https://rstudio.github.io/bslib/dev/articles/brand-yml/)
  article. (#1148)

## Improvements and bug fixes

* `navset_card_pills()`, `navset_card_underline()`,
  `navset_card_tabs()` fixed to now respect header/footer arguments
  (@tanho63, #1024)

* Fixed a bug in `bs_themer()` (and `bs_theme_preview()`) that caused
  it to stop applying changes if a Sass variable was `NULL`. (@meztez,
  #1112)

* Optimized for better performance the internal functions that compile
  Sass to call the `color-contrast()` algorithm. (#1140)

* `input_switch()` and `input_dark_mode()` can be included in Shiny's
  [bookmarking
  feature](https://shiny.posit.co/r/articles/share/bookmarking-state/). (#1166)

* Fixed an issue with the Shiny preset (`bs_theme(5, "shiny")`) that
  caused a floating underling to appear when a `nav_panel_hidden()`
  was used and active. (#1170)

* bslib now uses navbar markup with Bootstrap 5 that's closer to the
  expected markup for Bootstrap. We still include the `navbar-default`
  or `navbar-inverse` classes on the `<nav>` element, for backwards
  compatibility, but in apps that use Bootstrap 5 these classes have
  no styles. (#1146)

* The following functions are no longer marked "experimental":
  `accordion()`, `breakpoints()`, `card()`, `input_dark_mode()`,
  `input_switch()`, `layout_columns()`, `layout_column_wrap()`,
  `page_fillable()`, `page_sidebar()`, `layout_sidebar()`,
  `sidebar()`, `popover()`, `tooltip()` and `value_box()`.