Disable incompatible extension versions in extension view (#9938)

This PR makes it so extension versions that are incompatible with what
the current Zed instance supports are disabled in the UI, to prevent
attempting to install them.

Here's what it looks like in the extension version picker:

<img width="589" alt="Screenshot 2024-03-28 at 4 21 15 PM"
src="https://github.com/zed-industries/zed/assets/1486634/8ef11c72-c8f0-4de8-a73b-5c82e96f6bfe">

Release Notes:

- N/A

crates/extension/src/extension_manifest.rs

@@ -5,6 +5,7 @@ use language::LanguageServerName;
 use serde::{Deserialize, Serialize};
 use std::{
     ffi::OsStr,
+    fmt,
     path::{Path, PathBuf},
     sync::Arc,
 };
@@ -31,9 +32,16 @@ pub struct OldExtensionManifest {
     pub grammars: BTreeMap<Arc<str>, PathBuf>,
 }
 
+/// The schema version of the [`ExtensionManifest`].
 #[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Clone, Copy, Serialize, Deserialize)]
 pub struct SchemaVersion(pub i32);
 
+impl fmt::Display for SchemaVersion {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
+
 impl SchemaVersion {
     pub const ZERO: Self = Self(0);