doc: avoid colloquialism

I witnessed an English-as-a-second-language speaker puzzle over the word "borked" in our documentation today. Reword to avoid colloquialisms. It's more precise and clear this way anyway. Also reformat `Optional:` to be consistent with how it appears elsewhere in the doc. PR-URL: #12417 Reviewed-By: Richard Lau <[email protected]> Reviewed-By: Luigi Pinca <[email protected]> Reviewed-By: Sakthipriyan Vairamani <[email protected]> Reviewed-By: Gibson Fahnestock <[email protected]> Reviewed-By: James M Snell <[email protected]>

Author: Trott

COLLABORATOR_GUIDE.md

@@ -345,7 +345,7 @@ Additionally:
 
 ### Technical HOWTO
 
-_Optional:_ ensure that you are not in a borked `am`/`rebase`state
+Clear any `am`/`rebase`that may already be underway.
 
 ```text
 $ git am --abort