Update documentation-style-guide.md (#20777)

Updated the word usage in the documentation style guide with checkout and check out.

contribute/style-guides/documentation-style-guide.md

@@ -87,6 +87,15 @@ When possible, use the exact title of the page or section you are linking to as
 
 
 Grafana products has some words, abbreviations, and slang particular to this discourse community.
 Grafana products has some words, abbreviations, and slang particular to this discourse community.
 
 
+#### checkout, check out
+
+Two words if used as a verb, one word if used as a noun.
+
+**Examples**
+
+* Check out these new features!
+* Proceed to checkout.
+
 #### data source
 #### data source
 
 
 Two words, not one
 Two words, not one