Change &(dyn Any + Send) to &dyn Any. (#45)

The `Send` trait is useless for references.

src/panic.rs

@@ -23,7 +23,7 @@ pub fn reset_panic_info() {
     });
 }
 
-pub fn take_panic(panic: &(dyn Any + Send + 'static)) -> PanicInfo {
+pub fn take_panic(panic: &dyn Any) -> PanicInfo {
     PANIC_INFO
         .with(|pi| pi.borrow_mut().take())
         .unwrap_or_else(move || serialize_panic(panic))
@@ -57,7 +57,7 @@ pub fn init_panic_hook(capture_backtraces: BacktraceCapture) {
     }));
 }
 
-fn serialize_panic(panic: &(dyn Any + Send + 'static)) -> PanicInfo {
+fn serialize_panic(panic: &dyn Any) -> PanicInfo {
     PanicInfo::new(match panic.downcast_ref::<&'static str>() {
         Some(s) => s,
         None => match panic.downcast_ref::<String>() {