chore: Remove tasks.md (#10273)

Piotr Osiewicz created 

The file has been moved over to zed.dev repo and resurrected some time
ago.

Release Notes:

- N/A

Change summary

assets/settings/default.json | 5 +++++
docs/src/tasks.md            | 1 -
2 files changed, 5 insertions(+), 1 deletion(-)

Detailed changes

assets/settings/default.json 🔗 

@@ -652,5 +652,10 @@
   // Mostly useful for developers who are managing multiple instances of Zed.
   "dev": {
     // "theme": "Andromeda"
+  },
+  // Task-related settings.
+  "task": {
+    // Whether to show task status indicator in the status bar. Default: true
+    "show_status_indicator": true
   }
 }