Updated thresholds for writing lock/unlock (#214)

Guide updates for new thresholds at which writing ability is locked and unlocked.

documentation/contributing/writing-ability.md

@@ -25,12 +25,14 @@ To determine if a contributor is eligible to keep writing notes:
 
 - Community Notes considers a contributor's five most recent notes that have reached a status of Helpful or Not Helpful.
 - Notes with the status of Needs More Ratings aren't considered.
-- If 3 or more of these 5 most recent notes have reached the status of Not Helpful, the contributor’s ability to write new notes is temporarily locked.
+- A contributor’s ability to write new notes is temporarily locked if either (a) 3 or more of these 5 most recent notes have reached the status of Not Helpful, or (b) the contributor has a 0 or negative Writing Impact score, and a note reaches the status of Not Helpful.
 
-Contributors can unlock their note writing ability by increasing their Rating Impact by 5.
+Contributors can unlock their note writing ability by increasing their Rating Impact. The first time writing ability is locked, contributors need to increase their Rating Impact by 5 to unlock writing ability.
 
 For example: If a contributor's Rating Impact was 22 when their ability to write became locked, they must increase this score to 27 to unlock their ability to write.
 
+If a contributor’s writing ability is repeatedly locked, the additional Rating Impact needed to unlock it again increases by 5 each time.
+
 [Learn more about Rating Impact](./writing-and-rating-impact.md) and get tips on how to increase it.
 
 ### How can I avoid having my ability to write notes locked?