Introduce a new /delta command (#17903)

Release Notes:

- Added a new `/delta` command to re-insert changed files that were
previously included in a context.

---------

Co-authored-by: Roy <roy@anthropic.com>

crates/extension/src/extension_slash_command.rs

@@ -6,7 +6,7 @@ use assistant_slash_command::{
 };
 use futures::FutureExt;
 use gpui::{Task, WeakView, WindowContext};
-use language::LspAdapterDelegate;
+use language::{BufferSnapshot, LspAdapterDelegate};
 use ui::prelude::*;
 use wasmtime_wasi::WasiView;
 use workspace::Workspace;
@@ -82,6 +82,8 @@ impl SlashCommand for ExtensionSlashCommand {
     fn run(
         self: Arc<Self>,
         arguments: &[String],
+        _context_slash_command_output_sections: &[SlashCommandOutputSection<language::Anchor>],
+        _context_buffer: BufferSnapshot,
         _workspace: WeakView<Workspace>,
         delegate: Option<Arc<dyn LspAdapterDelegate>>,
         cx: &mut WindowContext,
@@ -121,6 +123,7 @@ impl SlashCommand for ExtensionSlashCommand {
                         range: section.range.into(),
                         icon: IconName::Code,
                         label: section.label.into(),
+                        metadata: None,
                     })
                     .collect(),
                 run_commands_in_text: false,