Make fetch slash command visible in the command selector (#21302)

The `/fetch` command is naturally already accessible via the completion
menu when you type / in the assistant panel, but it wasn't on the "Add
Context" command selector. I think it should! It's a super nice/powerful
one, and I've seen folks not knowing it existed. Side-note: maybe, in
the near future, it'd be best to rename it to "`/web`, as that's an
easier name to parse and assume what it does.

<img width="700" alt="Screenshot 2024-11-28 at 16 52 07"
src="https://github.com/user-attachments/assets/37134e1c-c788-48ca-81ae-d7416e8c8706">

Release Notes:

- N/A

crates/ui/src/components/icon.rs

@@ -160,7 +160,6 @@ pub enum IconName {
     Copy,
     CountdownTimer,
     CursorIBeam,
-    TextSnippet,
     Dash,
     DatabaseZap,
     Delete,
@@ -171,8 +170,8 @@ pub enum IconName {
     EllipsisVertical,
     Envelope,
     Escape,
-    Exit,
     ExpandVertical,
+    Exit,
     ExternalLink,
     Eye,
     File,
@@ -198,6 +197,7 @@ pub enum IconName {
     GenericMinimize,
     GenericRestore,
     Github,
+    Globe,
     Hash,
     HistoryRerun,
     Indicator,
@@ -223,13 +223,13 @@ pub enum IconName {
     PageUp,
     Pencil,
     Person,
+    PhoneIncoming,
     Pin,
     Play,
     Plus,
     PocketKnife,
     Public,
     PullRequest,
-    PhoneIncoming,
     Quote,
     RefreshTitle,
     Regex,
@@ -275,6 +275,7 @@ pub enum IconName {
     SwatchBook,
     Tab,
     Terminal,
+    TextSnippet,
     Trash,
     TrashAlt,
     Triangle,
@@ -287,11 +288,11 @@ pub enum IconName {
     Wand,
     Warning,
     WholeWord,
+    X,
     XCircle,
     ZedAssistant,
     ZedAssistantFilled,
     ZedXCopilot,
-    X,
 }
 
 impl From<IconName> for Icon {