docs: Format docs (#15352)

This PR formats the rest of the docs' source files.

I'll follow up with a CI check to ensure they stay formatted.

Release Notes:

- N/A

docs/src/languages/r.md

@@ -4,12 +4,12 @@ R support is available through the [R extension](https://github.com/ocsmit/zed-r
 
 ## Installation
 
-* [Install R](https://cloud.r-project.org/)
-* Install the R packages `languageserver` and `lintr`:
+- [Install R](https://cloud.r-project.org/)
+- Install the R packages `languageserver` and `lintr`:
 
 ```R
 install.packages("languageserver")
 install.packages("lintr")
 ```
 
-* Install the [R extension](https://github.com/ocsmit/zed-r) through Zed's extensions
+- Install the [R extension](https://github.com/ocsmit/zed-r) through Zed's extensions