Remove edit action markers from edit_prompt.md (#27785)

https://github.com/zed-industries/zed/pull/27778 removed most
occurrences, but there were still some more in `edit_prompt.md`

Release Notes:

- N/A

crates/assistant_tools/src/edit_files_tool.rs

@@ -6,7 +6,7 @@ use crate::schema::json_schema_for;
 use anyhow::{anyhow, Context, Result};
 use assistant_tool::{ActionLog, Tool};
 use collections::HashSet;
-use edit_action::{EditAction, EditActionParser};
+use edit_action::{edit_model_prompt, EditAction, EditActionParser};
 use futures::{channel::mpsc, SinkExt, StreamExt};
 use gpui::{App, AppContext, AsyncApp, Entity, Task};
 use language_model::LanguageModelToolSchemaFormat;
@@ -230,10 +230,7 @@ impl EditToolRequest {
 
         messages.push(LanguageModelRequestMessage {
             role: Role::User,
-            content: vec![
-                include_str!("./edit_files_tool/edit_prompt.md").into(),
-                input.edit_instructions.into(),
-            ],
+            content: vec![edit_model_prompt().into(), input.edit_instructions.into()],
             cache: false,
         });