Additions for settings profile selector (#35439)

- Added profile selector to `zed > settings` submenu.
- Added examples to the `default.json` docs.
- Reduced length of the setting description that shows on autocomplete,
since it was cutoff in the autocomplete popover.


Release Notes:

- N/A

crates/settings/src/settings_store.rs

@@ -1078,7 +1078,7 @@ impl SettingsStore {
                         "preview": zed_settings_override_ref,
                         "profiles": {
                             "type": "object",
-                            "description": "Configures any number of settings profiles that are temporarily applied when selected from `settings profile selector: toggle`.",
+                            "description": "Configures any number of settings profiles.",
                             "additionalProperties": zed_settings_override_ref
                         }
                     }