Revert "Add a way to toggle inlay hints with modifiers" (#25764)

This PR caused inlay hints to show on every modifiers press

Reverts zed-industries/zed#25752

Release Notes:

- N/A

crates/gpui/src/platform/keystroke.rs

@@ -1,5 +1,4 @@
-use schemars::JsonSchema;
-use serde::{Deserialize, Serialize};
+use serde::Deserialize;
 use std::{
     error::Error,
     fmt::{Display, Write},
@@ -307,29 +306,24 @@ impl std::fmt::Display for Keystroke {
 }
 
 /// The state of the modifier keys at some point in time
-#[derive(Copy, Clone, Debug, Eq, PartialEq, Default, Serialize, Deserialize, Hash, JsonSchema)]
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Default, Deserialize, Hash)]
 pub struct Modifiers {
     /// The control key
-    #[serde(default)]
     pub control: bool,
 
     /// The alt key
     /// Sometimes also known as the 'meta' key
-    #[serde(default)]
     pub alt: bool,
 
     /// The shift key
-    #[serde(default)]
     pub shift: bool,
 
     /// The command key, on macos
     /// the windows key, on windows
     /// the super key, on linux
-    #[serde(default)]
     pub platform: bool,
 
     /// The function key
-    #[serde(default)]
     pub function: bool,
 }