debugger: Fix nits (#30632)

Release Notes:

- N/A

---------

Co-authored-by: Anthony Eid <hello@anthonyeid.me>

crates/language/src/language_settings.rs

@@ -980,8 +980,8 @@ pub struct InlayHintSettings {
     pub enabled: bool,
     /// Global switch to toggle inline values on and off.
     ///
-    /// Default: false
-    #[serde(default)]
+    /// Default: true
+    #[serde(default = "default_true")]
     pub show_value_hints: bool,
     /// Whether type hints should be shown.
     ///