Bump workspace to edition 2024

- edition = "2024" in the workspace manifest and rsdosedit
- extern blocks must be unsafe: interrupts.rs ISR stubs -> unsafe extern "C"
- #[no_mangle] -> #[unsafe(no_mangle)] (efi_main, isr_dispatch)
- One missed static-mut read in free_list_insert wrapped in an explicit
  unsafe block (edition 2024 removed the implicit unsafe context inside
  unsafe fns)
- rustfmt reflows for 2024: nested if-lets become let-chains, imports
  re-sorted, rsdosedit help-screen box rows wrapped

No codegen-affecting changes. Validated: cargo check/clippy/fmt clean
(host + uefi target), make test-disk PASS, editor round-trip PASS.

1 files changed, 5 insertions, 5 deletions

diff --git a/rsnix/src/fs.rs b/rsnix/src/fs.rs
index 2a1a3e3..a71e51a 100644
--- a/rsnix/src/fs.rs
+++ b/rsnix/src/fs.rs
@@ -92,10 +92,10 @@ fn add(name: &str, parent: Option<usize>, kind: FileType, data: NodeData) -> usi
         data,
         removed: false,
     });
-    if let Some(p) = parent {
-        if let NodeData::Dir(v) = &mut nodes()[p].data {
-            v.push(h);
-        }
+    if let Some(p) = parent
+        && let NodeData::Dir(v) = &mut nodes()[p].data
+    {
+        v.push(h);
     }
     h
 }
@@ -224,7 +224,7 @@ pub fn resolve(path: &str) -> Option<usize> {
         return None;
     }
     let mut cur = 0usize; // root
-                          // (vol, cluster, parent, name) of directories descended into under /disk.
+    // (vol, cluster, parent, name) of directories descended into under /disk.
     let mut dstack: Vec<(usize, u32, u32, String)> = Vec::new();
     for seg in path.split('/') {
         match seg {