Re-build index.Rmd (GitHub Actions)

index.md

 **xaringanthemer** is <kbd>Tab</kbd> friendly – [use autocomplete to
 explore](#theme-settings) the [template
 variables](vignettes/template-variables.md) that you can adjust in each
-of the themes!
+of the themes\!
 
 <img src="https://raw.githubusercontent.com/gadenbuie/xaringanthemer/assets/example-rstudio-completion.gif" alt="Demonstration of argument auto-completion with RStudio" data-external="1" />
 
 Presentation* from the New R Markdown Document menu in RStudio.
 
 <center>
+
 <img src="https://raw.githubusercontent.com/gadenbuie/xaringanthemer/assets/rmarkdown-template-screenshot.png" alt="The 'New R Markdown Document' menu in RStudio" data-external="1" />
+
 </center>
 
 ## Features
 
-There’s a lot more that **xaringanthemer** can do! [Discover
+There’s a lot more that **xaringanthemer** can do\! [Discover
 xaringanthemer’s
 features.](https://pkg.garrickadenbuie.com/xaringanthemer/articles/xaringanthemer.html)