Open workflow step editors as preview tabs (#15928)

This PR opens workflow step editors as preview tabs and closes them upon
exiting the step if they are still in preview mode and they weren't
already open before entering the step.

Making this work was tricky, because we often edit the buffer as part of
displaying the workflow step suggestions to create empty lines where we
can generate. We undo these edits if the transformation is not applied,
but they were causing the preview to be dismissed.

After trying a few approaches, I decided to give workspace `Item`s a
`preserve_preview` method that defaults to false. When the workspace
sees an edit event for the item, it checks if the item wants to preserve
its preview. For buffers, after editing, you can call `refresh_preview`,
which sets a preview version to the current version of the buffer. Any
edits after this version will cause preview to not be preserved.

One final issue is with async auto-indent. To ensure these async edits
don't dismiss the preview, I automatically refresh the preview version
if preview was preserved prior to performing the auto-indent. The
assumption is that these are edits created by other edits, and if we
didn't want to dismiss the preview with the originating edits, then the
auto-indent edits shouldn't dismiss it either.

Release Notes:

- N/A

---------

Co-authored-by: Jason <jason@zed.dev>

assets/prompts/step_resolution.hbs

@@ -1,4 +1,4 @@
-Your task is to map a step from the conversation above to operations on symbols inside the provided source files.
+Your task is to map a step from the conversation above to suggestions on symbols inside the provided source files.
 
 Guidelines:
 - There's no need to describe *what* to do, just *where* to do it.
@@ -6,13 +6,13 @@ Guidelines:
 - Don't create and then update a file.
 - We'll create it in one shot.
 - Prefer updating symbols lower in the syntax tree if possible.
-- Never include operations on a parent symbol and one of its children in the same operations block.
-- Never nest an operation with another operation or include CDATA or other content. All operations are leaf nodes.
+- Never include suggestions on a parent symbol and one of its children in the same suggestions block.
+- Never nest an operation with another operation or include CDATA or other content. All suggestions are leaf nodes.
 - Include a description attribute for each operation with a brief, one-line description of the change to perform.
-- Descriptions are required for all operations except delete.
-- When generating multiple operations, ensure the descriptions are specific to each individual operation.
+- Descriptions are required for all suggestions except delete.
+- When generating multiple suggestions, ensure the descriptions are specific to each individual operation.
 - Avoid referring to the location in the description. Focus on the change to be made, not the location where it's made. That's implicit with the symbol you provide.
-- Don't generate multiple operations at the same location. Instead, combine them together in a single operation with a succinct combined description.
+- Don't generate multiple suggestions at the same location. Instead, combine them together in a single operation with a succinct combined description.
 
 Example 1:
 
@@ -33,12 +33,12 @@ impl Rectangle {
 <step>Add new methods 'calculate_area' and 'calculate_perimeter' to the Rectangle struct</step>
 <step>Implement the 'Display' trait for the Rectangle struct</step>
 
-What are the operations for the step: <step>Add a new method 'calculate_area' to the Rectangle struct</step>
+What are the suggestions for the step: <step>Add a new method 'calculate_area' to the Rectangle struct</step>
 
 A (wrong):
 {
   "title": "Add Rectangle methods",
-  "operations": [
+  "suggestions": [
     {
       "kind": "AppendChild",
       "path": "src/shapes.rs",
@@ -59,7 +59,7 @@ This demonstrates what NOT to do. NEVER append multiple children at the same loc
 A (corrected):
 {
   "title": "Add Rectangle methods",
-  "operations": [
+  "suggestions": [
     {
       "kind": "AppendChild",
       "path": "src/shapes.rs",
@@ -70,12 +70,12 @@ A (corrected):
 }
 
 User:
-What are the operations for the step: <step>Implement the 'Display' trait for the Rectangle struct</step>
+What are the suggestions for the step: <step>Implement the 'Display' trait for the Rectangle struct</step>
 
 A:
 {
   "title": "Implement Display for Rectangle",
-  "operations": [
+  "suggestions": [
     {
       "kind": "InsertSiblingAfter",
       "path": "src/shapes.rs",
@@ -109,12 +109,12 @@ impl User {
 <step>Update the 'print_info' method to use formatted output</step>
 <step>Remove the 'email' field from the User struct</step>
 
-What are the operations for the step: <step>Update the 'print_info' method to use formatted output</step>
+What are the suggestions for the step: <step>Update the 'print_info' method to use formatted output</step>
 
 A:
 {
   "title": "Use formatted output",
-  "operations": [
+  "suggestions": [
     {
       "kind": "Update",
       "path": "src/user.rs",
@@ -125,12 +125,12 @@ A:
 }
 
 User:
-What are the operations for the step: <step>Remove the 'email' field from the User struct</step>
+What are the suggestions for the step: <step>Remove the 'email' field from the User struct</step>
 
 A:
 {
   "title": "Remove email field",
-  "operations": [
+  "suggestions": [
       {
         "kind": "Delete",
         "path": "src/user.rs",
@@ -163,12 +163,12 @@ impl Vehicle {
 <step>Add a 'use std::fmt;' statement at the beginning of the file</step>
 <step>Add a new method 'start_engine' in the Vehicle impl block</step>
 
-What are the operations for the step: <step>Add a 'use std::fmt;' statement at the beginning of the file</step>
+What are the suggestions for the step: <step>Add a 'use std::fmt;' statement at the beginning of the file</step>
 
 A:
 {
   "title": "Add use std::fmt statement",
-  "operations": [
+  "suggestions": [
     {
       "kind": "PrependChild",
       "path": "src/vehicle.rs",
@@ -178,12 +178,12 @@ A:
 }
 
 User:
-What are the operations for the step: <step>Add a new method 'start_engine' in the Vehicle impl block</step>
+What are the suggestions for the step: <step>Add a new method 'start_engine' in the Vehicle impl block</step>
 
 A:
 {
   "title": "Add start_engine method",
-  "operations": [
+  "suggestions": [
     {
       "kind": "InsertSiblingAfter",
       "path": "src/vehicle.rs",
@@ -222,12 +222,12 @@ impl Employee {
 
 <step>Make salary an f32</step>
 
-What are the operations for the step: <step>Make salary an f32</step>
+What are the suggestions for the step: <step>Make salary an f32</step>
 
 A (wrong):
 {
   "title": "Change salary to f32",
-  "operations": [
+  "suggestions": [
     {
       "kind": "Update",
       "path": "src/employee.rs",
@@ -248,7 +248,7 @@ This example demonstrates what not to do. `struct Employee salary` is a child of
 A (corrected):
 {
   "title": "Change salary to f32",
-  "operations": [
+  "suggestions": [
     {
       "kind": "Update",
       "path": "src/employee.rs",
@@ -259,12 +259,12 @@ A (corrected):
 }
 
 User:
-What are the correct operations for the step: <step>Remove the 'department' field and update the 'print_details' method</step>
+What are the correct suggestions for the step: <step>Remove the 'department' field and update the 'print_details' method</step>
 
 A:
 {
   "title": "Remove department",
-  "operations": [
+  "suggestions": [
     {
       "kind": "Delete",
       "path": "src/employee.rs",
@@ -311,7 +311,7 @@ impl Game {
 A:
 {
   "title": "Add level field to Player",
-  "operations": [
+  "suggestions": [
     {
       "kind": "InsertSiblingAfter",
       "path": "src/game.rs",
@@ -349,7 +349,7 @@ impl Config {
 A:
 {
   "title": "Add load_from_file method",
-  "operations": [
+  "suggestions": [
     {
       "kind": "PrependChild",
       "path": "src/config.rs",
@@ -389,7 +389,7 @@ impl Database {
 A:
 {
   "title": "Add error handling to query",
-  "operations": [
+  "suggestions": [
     {
       "kind": "PrependChild",
       "path": "src/database.rs",
@@ -410,4 +410,4 @@ A:
   ]
 }
 
-Now generate the operations for the following step:
+Now generate the suggestions for the following step: