bevy_time: Apply `#![deny(clippy::allow_attributes, clippy::allow_att…

…ributes_without_reason)]` (#17210)

# Objective
- #17111

## Solution
Set the `clippy::allow_attributes` and
`clippy::allow_attributes_without_reason` lints to `deny`, and bring
`bevy_time` in line with the new restrictions.

No code changes have been made - except if a lint that was previously
`allow(...)`'d could be removed via small code changes. For example,
`unused_variables` can be handled by adding a `_` to the beginning of a
field's name.

## Testing
`cargo clippy`, `cargo clippy --package bevy_time` and `cargo test
--package bevy_time` were run, and no errors were encountered.

crates/bevy_time/src/lib.rs

@@ -1,6 +1,11 @@
 #![doc = include_str!("../README.md")]
 #![cfg_attr(docsrs, feature(doc_auto_cfg))]
 #![forbid(unsafe_code)]
+#![deny(
+    clippy::allow_attributes,
+    clippy::allow_attributes_without_reason,
+    reason = "See #17111; To be removed once all crates are in-line with these attributes"
+)]
 #![doc(
     html_logo_url = "https://bevyengine.org/assets/icon.png",
     html_favicon_url = "https://bevyengine.org/assets/icon.png"

crates/bevy_time/src/timer.rs

@@ -447,7 +447,6 @@ pub enum TimerMode {
 }
 
 #[cfg(test)]
-#[allow(clippy::float_cmp)]
 mod tests {
     use super::*;