Default `#[schemars(deny_unknown_fields)] for json-language-server schemas (#33883)

Followup to #33678, doing the same thing for all JSON Schema files
provided to json-language-server

Release Notes:

* Added warnings for unknown fields when editing `tasks.json` /
`snippets.json`.

crates/language/src/language_settings.rs

@@ -18,10 +18,10 @@ use serde::{
 
 use settings::{
     ParameterizedJsonSchema, Settings, SettingsLocation, SettingsSources, SettingsStore,
-    replace_subschema,
 };
 use shellexpand;
 use std::{borrow::Cow, num::NonZeroU32, path::Path, slice, sync::Arc};
+use util::schemars::replace_subschema;
 use util::serde::default_true;
 
 /// Initializes the language settings.