Add new make-file-executable API for extensions (#10047)

This PR adds a new function, `make-file-executable`, to the Zed
extension API that can be used to mark a given file as executable
(typically the language server binary).

This is available in v0.0.5 of the `zed_extension_api` crate.

We also reworked how we represent the various WIT versions on disk to
make it a bit clearer what the version number entails.

Release Notes:

- N/A

---------

Co-authored-by: Max <max@zed.dev>

extensions/zig/src/zig.rs

@@ -78,6 +78,8 @@ impl ZigExtension {
             )
             .map_err(|e| format!("failed to download file: {e}"))?;
 
+            zed::make_file_executable(&binary_path)?;
+
             let entries =
                 fs::read_dir(".").map_err(|e| format!("failed to list working directory {e}"))?;
             for entry in entries {