Refactor script class handling and improve imports in git.rs and ref_properties.rs

- Moved the `is_script_class` function to the `snapshot` module for better organization and reusability.
- Updated imports in `git.rs` and `ref_properties.rs` to reflect the new location of `is_script_class`, enhancing code clarity and maintainability.

These changes aim to streamline script class management and improve the overall structure of the codebase.

src/syncback/ref_properties.rs

@@ -11,6 +11,7 @@ use rbx_dom_weak::{
 
 use crate::{
     ref_attribute_name, ref_target_attribute_name,
+    snapshot::is_script_class,
     syncback::{name_needs_slugify, slugify_name},
     REF_ID_ATTRIBUTE_NAME, REF_PATH_ATTRIBUTE_PREFIX, REF_POINTER_ATTRIBUTE_PREFIX,
 };
@@ -131,10 +132,6 @@ fn tentative_fs_name(inst: &Instance) -> String {
     format!("{slug}.{extension}")
 }
 
-fn is_script_class(class: &str) -> bool {
-    matches!(class, "Script" | "LocalScript" | "ModuleScript")
-}
-
 pub struct RefLinks {
     /// Refs that use path-based linking (path is unique).
     path_links: HashMap<Ref, Vec<PathRefLink>>,