Improve keymap json schema (#23044)

Also:

* Adds `impl_internal_actions!` for deriving the `Action` trait without
registering.

* Removes some deserializers that immediately fail in favor of
`#[serde(skip)]` on fields where they were used. This also omits them
from the schema.

Release Notes:

- Keymap settings file now has more JSON schema information to inform
`json-language-server` completions and info, particularly for actions
that take input.

crates/assistant/src/assistant.rs

@@ -26,7 +26,7 @@ pub use context::*;
 pub use context_store::*;
 use feature_flags::FeatureFlagAppExt;
 use fs::Fs;
-use gpui::impl_actions;
+use gpui::impl_internal_actions;
 use gpui::{actions, AppContext, Global, SharedString, UpdateGlobal};
 pub(crate) use inline_assistant::*;
 use language_model::{
@@ -74,13 +74,13 @@ actions!(
     ]
 );
 
-#[derive(PartialEq, Clone, Deserialize)]
+#[derive(PartialEq, Clone)]
 pub enum InsertDraggedFiles {
     ProjectPaths(Vec<PathBuf>),
     ExternalFiles(Vec<PathBuf>),
 }
 
-impl_actions!(assistant, [InsertDraggedFiles]);
+impl_internal_actions!(assistant, [InsertDraggedFiles]);
 
 const DEFAULT_CONTEXT_LINES: usize = 50;