Settings refactor (#38367)

Co-Authored-By: Ben K <ben@zed.dev>
Co-Authored-By: Anthony <anthony@zed.dev>
Co-Authored-By: Mikayla <mikayla@zed.dev>

Release Notes:

- settings: Major internal changes to settings. The primary user-facing
effect is that some settings which did not make sense in project
settings files are no-longer read from there. (For example the inline
blame settings)

---------

Co-authored-by: Ben Kunkle <ben@zed.dev>
Co-authored-by: Mikayla Maki <mikayla.c.maki@gmail.com>
Co-authored-by: Anthony <anthony@zed.dev>

crates/settings/src/settings_file.rs

@@ -1,4 +1,4 @@
-use crate::{Settings, settings_store::SettingsStore};
+use crate::{settings_content::SettingsContent, settings_store::SettingsStore};
 use collections::HashSet;
 use fs::{Fs, PathEventKind};
 use futures::{StreamExt, channel::mpsc};
@@ -126,10 +126,10 @@ pub fn watch_config_dir(
     rx
 }
 
-pub fn update_settings_file<T: Settings>(
+pub fn update_settings_file(
     fs: Arc<dyn Fs>,
     cx: &App,
-    update: impl 'static + Send + FnOnce(&mut T::FileContent, &App),
+    update: impl 'static + Send + FnOnce(&mut SettingsContent, &App),
 ) {
-    SettingsStore::global(cx).update_settings_file::<T>(fs, update);
+    SettingsStore::global(cx).update_settings_file(fs, update);
 }