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/picker/Cargo.toml

@@ -20,6 +20,7 @@ anyhow.workspace = true
 editor.workspace = true
 gpui.workspace = true
 menu.workspace = true
+schemars.workspace = true
 serde.workspace = true
 ui.workspace = true
 workspace.workspace = true

crates/picker/src/picker.rs

@@ -7,6 +7,7 @@ use gpui::{
     ViewContext, WindowContext,
 };
 use head::Head;
+use schemars::JsonSchema;
 use serde::Deserialize;
 use std::{sync::Arc, time::Duration};
 use ui::{prelude::*, v_flex, Color, Divider, Label, ListItem, ListItemSpacing};
@@ -24,7 +25,7 @@ actions!(picker, [ConfirmCompletion]);
 
 /// ConfirmInput is an alternative editor action which - instead of selecting active picker entry - treats pickers editor input literally,
 /// performing some kind of action on it.
-#[derive(PartialEq, Clone, Deserialize, Default)]
+#[derive(Clone, PartialEq, Deserialize, JsonSchema, Default)]
 pub struct ConfirmInput {
     pub secondary: bool,
 }