Restructure workflow step resolution and fix inserting newlines (#15720)

Release Notes:

- N/A

---------

Co-authored-by: Nathan <nathan@zed.dev>

Cargo.lock

@@ -422,7 +422,6 @@ dependencies = [
  "settings",
  "similar",
  "smol",
- "strsim 0.11.1",
  "telemetry_events",
  "terminal",
  "terminal_view",
@@ -5952,6 +5951,7 @@ dependencies = [
  "similar",
  "smallvec",
  "smol",
+ "strsim 0.11.1",
  "sum_tree",
  "task",
  "text",
@@ -5994,6 +5994,7 @@ dependencies = [
  "menu",
  "ollama",
  "open_ai",
+ "parking_lot",
  "project",
  "proto",
  "rand 0.8.5",