assistant: Insert creases for tool uses (#17330)

This PR makes it so we create creases for each of the tool uses in the
context editor.

<img width="1290" alt="Screenshot 2024-09-03 at 5 37 33 PM"
src="https://github.com/user-attachments/assets/94e943fd-3f05-4bc4-9672-94bff42ec500">

Release Notes:

- N/A

crates/ui/src/components/icon.rs

@@ -215,6 +215,7 @@ pub enum IconName {
     Pin,
     Play,
     Plus,
+    PocketKnife,
     Public,
     PullRequest,
     Quote,
@@ -386,6 +387,7 @@ impl IconName {
             IconName::Pin => "icons/pin.svg",
             IconName::Play => "icons/play.svg",
             IconName::Plus => "icons/plus.svg",
+            IconName::PocketKnife => "icons/pocket_knife.svg",
             IconName::Public => "icons/public.svg",
             IconName::PullRequest => "icons/pull_request.svg",
             IconName::Quote => "icons/quote.svg",