new rustc versions require that `no_mangle` not be present on language items

[TheAwesome98-Real]

this diff fixes the error:

diff --git a/luma_runtime/src/lib.rs b/luma_runtime/src/lib.rs
index cfedcf5..37b98ec 100644
--- a/luma_runtime/src/lib.rs
+++ b/luma_runtime/src/lib.rs
@@ -69,7 +69,7 @@ impl Termination for () {}
 
 /// This function is called on panic.
 #[cfg_attr(not(test), panic_handler)]
-#[unsafe(no_mangle)]
+//#[unsafe(no_mangle)]
 fn panic(info: &PanicInfo) -> ! {
     println!("{}", info);
     loop {}
@@ -77,5 +77,5 @@ fn panic(info: &PanicInfo) -> ! {
 
 /// Error handler personality language item (current no-op, to satisfy clippy).
 #[cfg_attr(not(test), lang = "eh_personality")]
-#[unsafe(no_mangle)]
+//#[unsafe(no_mangle)]
 extern "C" fn rust_eh_personality() {}