editor: Add setting for snippet sorting behavior for code completion (#29429)

Added `snippet_sort_order`, which determines how snippets are sorted
relative to other completion items. It can have the values `top`,
`bottom`, or `inline`, with `inline` being the default.

This mimics VS Code’s setting:
https://code.visualstudio.com/docs/editing/intellisense#_snippets-in-suggestions

Release Notes:

- Added support for `snippet_sort_order` to control snippet sorting
behavior in code completion menus.

assets/settings/default.json

@@ -167,7 +167,23 @@
   // Default: not set, defaults to "bar"
   "cursor_shape": null,
   // Determines when the mouse cursor should be hidden in an editor or input box.
+  //
+  // 1. Never hide the mouse cursor:
+  //    "never"
+  // 2. Hide only when typing:
+  //    "on_typing"
+  // 3. Hide on both typing and cursor movement:
+  //    "on_typing_and_movement"
   "hide_mouse": "on_typing_and_movement",
+  // Determines how snippets are sorted relative to other completion items.
+  //
+  // 1. Place snippets at the top of the completion list:
+  //    "top"
+  // 2. Place snippets normally without any preference:
+  //    "inline"
+  // 3. Place snippets at the bottom of the completion list:
+  //    "bottom"
+  "snippet_sort_order": "inline",
   // How to highlight the current line in the editor.
   //
   // 1. Don't highlight the current line: