message: tracing: avoid wildcard imports
  ## Motivation
  The current implementation triggers [`clippy::wildcard_imports`][1]
  warning.
  [1]:
  ## Solution
  Import items explicitly instead of using `*`.
diff: @@ -591,7 +591,7 @@ macro_rules! event {
  );
  if $crate::level_enabled!($lvl) {
  - use $crate::__macro_support::*;
  + use $crate::__macro_support::Callsite as _;
  static CALLSITE: $crate::__macro_support::MacroCallsite = $crate::callsite2! {
  name: concat!(
  "event ",
  @@ -638,7 +638,7 @@ macro_rules! event {
  $($fields)*
  );
  if $crate::level_enabled!($lvl) {
  - use $crate::__macro_support::*;
  + use $crate::__macro_support::Callsite as _;
  static CALLSITE: $crate::__macro_support::MacroCallsite = $crate::callsite2! {
  name: concat!(
  "event ",
  