Revert "Add setting to show/hide title bar (#37428)" (#38756)

Closes https://github.com/zed-industries/zed/issues/38547

Release Notes:

- Reverted the ability to show/hide the titlebar. This caused rendering
bugs on
macOS, and we're preparing for the redesign which requires the toolbar
being present.

---------

Co-authored-by: Kirill Bulatov <kirill@zed.dev>

crates/settings/src/settings_content.rs

@@ -237,10 +237,6 @@ pub enum BaseKeymapContent {
 #[skip_serializing_none]
 #[derive(Clone, PartialEq, Default, Serialize, Deserialize, JsonSchema, MergeFrom, Debug)]
 pub struct TitleBarSettingsContent {
-    /// Controls when the title bar is visible: "always" | "never" | "hide_in_full_screen".
-    ///
-    /// Default: "always"
-    pub show: Option<TitleBarVisibility>,
     /// Whether to show the branch icon beside branch switcher in the title bar.
     ///
     /// Default: false
@@ -271,14 +267,6 @@ pub struct TitleBarSettingsContent {
     pub show_menus: Option<bool>,
 }
 
-#[derive(Copy, Clone, PartialEq, Serialize, Deserialize, JsonSchema, MergeFrom, Debug)]
-#[serde(rename_all = "snake_case")]
-pub enum TitleBarVisibility {
-    Always,
-    Never,
-    HideInFullScreen,
-}
-
 /// Configuration of audio in Zed.
 #[skip_serializing_none]
 #[derive(Clone, PartialEq, Default, Serialize, Deserialize, JsonSchema, MergeFrom, Debug)]