treewide: fix clippy lints

Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: I411be69ff31f9cb39cd4cdebc8985b366a6a6964

src/error.rs

@@ -1,3 +1,5 @@
+use std::fmt::Write;
+
 use thiserror::Error;
 
 pub type Result<T> = std::result::Result<T, PakkerError>;
@@ -11,6 +13,7 @@ pub enum ErrorSeverity {
   /// Warning - operation can continue but may have issues
   Warning,
   /// Info - informational message
+  #[expect(dead_code, reason = "reserved for future use")]
   Info,
 }
 
@@ -177,7 +180,7 @@ fn format_multiple_errors(errors: &[PakkerError]) -> String {
 
   let mut msg = format!("{} errors occurred:\n", errors.len());
   for (idx, error) in errors.iter().enumerate() {
-    msg.push_str(&format!("  {}. {}\n", idx + 1, error));
+    let _ = writeln!(msg, "  {}. {}", idx + 1, error);
   }
   msg
 }