Fix some pkgdown hyperlinks

Author: cpsievert

NEWS.md

@@ -16,7 +16,7 @@
 
 * Closed #236, #230, #242, #187, #215, #250: Addressed various cosmetic issues with CSS (#249). 
 * Closed #289: collapsed navbar toggle now correctly floats to the right (#290).
-* Closed rstudio/flexdashboard#316: fixed an issue with navbar nav spacing/alignment (#286).
+* Closed [rstudio/flexdashboard#316](https://github.com/rstudio/flexdashboard/issues/316): fixed an issue with navbar nav spacing/alignment (#286).
 
 # bslib 0.2.4
 

vignettes/bslib.Rmd

@@ -368,7 +368,7 @@ Below is a list of known-to-be themeable HTML components that "just work" well w
 * All of "core" Shiny UI (e.g., `sliderInput()`, `selectInput()`, `tabPanel()`, `navbarPage()`, etc.) 
   * The one exception is `plotOutput()`, but in that case, [the `{thematic}` package can be used to essentially translate CSS to R plot theming defaults](https://rstudio.github.io/thematic/articles/auto.html). Just put `thematic_shiny()` in your Shiny apps and `thematic_rmd()` in your R Markdown documents.
 
-* All of `rmarkdown::html_document()` specific [features](https://bookdown.org/yihui/rmarkdown/html-document.html) as well as [`{flexdashboard}`](https://flexdashboard-pkg.netlify.app/articles/articles/theme.html).
+* All of `rmarkdown::html_document()` specific [features](https://bookdown.org/yihui/rmarkdown/html-document.html) as well as [`{flexdashboard}`](https://flexdashboard-pkg.netlify.app/articles/theme.html).
 
 * Any un-styled HTML content (e.g., `tags$input(type = "checkbox")`).
 

vignettes/utility-classes.Rmd

@@ -8,7 +8,7 @@ Bootstrap 4 (and above) comes with a suite of handy utility classes for handling
 ## Add margin
 
 If you look at [the source](https://github.com/rstudio/bslib/tree/master/inst/themer-demo) for the theme demo app, the `actionButton()` logic makes use of the margin spacing (`m-2`) to add some spacing between the buttons (they also make use of [button modifier classes](
-/components/buttons/) to achieve their different background colors).
+https://getbootstrap.com/docs/4.6/components/buttons/) to achieve their different background colors).
 
 ``` {.r}
 actionButton("primary", "Primary", icon("product-hunt"), class = "btn-primary m-2")