clippy_lints: Update empty_loop lint

We also update the documentation to note that the remediations are
different for `std` and `no_std` crates.

Signed-off-by: Joe Richey <joerichey@google.com>

3 files changed, 10 insertions, 4 deletions

diff --git a/tests/ui/crashes/ice-360.stderr b/tests/ui/crashes/ice-360.stderr
index 84e31eaf2e9..bb03ce40355 100644
--- a/tests/ui/crashes/ice-360.stderr
+++ b/tests/ui/crashes/ice-360.stderr
@@ -12,13 +12,14 @@ LL | |     }
    |
    = note: `-D clippy::while-let-loop` implied by `-D warnings`
 
-error: empty `loop {}` detected. You may want to either use `panic!()` or add `std::thread::sleep(..);` to the loop body.
+error: empty `loop {}` wastes CPU cycles
   --> $DIR/ice-360.rs:10:9
    |
 LL |         loop {}
    |         ^^^^^^^
    |
    = note: `-D clippy::empty-loop` implied by `-D warnings`
+   = help: You should either use `panic!()` or add `std::thread::sleep(..);` to the loop body.
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/empty_loop.stderr b/tests/ui/empty_loop.stderr
index e44c58ea770..fd3979f259a 100644
--- a/tests/ui/empty_loop.stderr
+++ b/tests/ui/empty_loop.stderr
@@ -1,22 +1,27 @@
-error: empty `loop {}` detected. You may want to either use `panic!()` or add `std::thread::sleep(..);` to the loop body.
+error: empty `loop {}` wastes CPU cycles
   --> $DIR/empty_loop.rs:9:5
    |
 LL |     loop {}
    |     ^^^^^^^
    |
    = note: `-D clippy::empty-loop` implied by `-D warnings`
+   = help: You should either use `panic!()` or add `std::thread::sleep(..);` to the loop body.
 
-error: empty `loop {}` detected. You may want to either use `panic!()` or add `std::thread::sleep(..);` to the loop body.
+error: empty `loop {}` wastes CPU cycles
   --> $DIR/empty_loop.rs:11:9
    |
 LL |         loop {}
    |         ^^^^^^^
+   |
+   = help: You should either use `panic!()` or add `std::thread::sleep(..);` to the loop body.
 
-error: empty `loop {}` detected. You may want to either use `panic!()` or add `std::thread::sleep(..);` to the loop body.
+error: empty `loop {}` wastes CPU cycles
   --> $DIR/empty_loop.rs:15:9
    |
 LL |         'inner: loop {}
    |         ^^^^^^^^^^^^^^^
+   |
+   = help: You should either use `panic!()` or add `std::thread::sleep(..);` to the loop body.
 
 error: aborting due to 3 previous errors
 
diff --git a/tests/ui/issue-3746.rs b/tests/ui/empty_loop_no_std.rs
index 879d1d5d916..879d1d5d916 100644
--- a/tests/ui/issue-3746.rs
+++ b/tests/ui/empty_loop_no_std.rs