docs: Fix typo in minimap docs (#57568)

The "all_editor" option for the `minimap.display_in` key is invalid. The
correct option is "all_editors".

Self-Review Checklist:

- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Release Notes:

- N/A

docs/src/visual-customization.md

@@ -281,7 +281,7 @@ TBD: Centered layout related settings
   // Minimap related settings
   "minimap": {
     "show": "never",                // When to show (auto, always, never)
-    "display_in": "active_editor",  // Where to show (active_editor, all_editor)
+    "display_in": "active_editor",  // Where to show (active_editor, all_editors)
     "thumb": "always",              // When to show thumb (always, hover)
     "thumb_border": "left_open",    // Thumb border (left_open, right_open, full, none)
     "max_width_columns": 80,        // Maximum width of minimap