chore: fix new Clippy lints in code that is not usually checked

src/deflate/mod.rs

@@ -1,8 +1,9 @@
 mod deflater;
+use std::{fmt, fmt::Display};
+
 pub use deflater::{crc32, deflate, inflate};
 
 use crate::{PngError, PngResult};
-use std::{fmt, fmt::Display};
 
 #[cfg(feature = "zopfli")]
 mod zopfli_oxipng;

src/lib.rs

@@ -673,7 +673,7 @@ fn copy_permissions(metadata_input: &Metadata, out_file: &File) -> PngResult<()>
 }
 
 #[cfg(not(feature = "filetime"))]
-fn copy_times(_: &Metadata, _: &Path) -> PngResult<()> {
+const fn copy_times(_: &Metadata, _: &Path) -> PngResult<()> {
     Ok(())
 }
 

src/sanity_checks.rs

@@ -44,7 +44,7 @@ fn load_png_image_from_memory(png_data: &[u8]) -> Result<Vec<RgbaImage>, image::
         decoder
             .apng()?
             .into_frames()
-            .map(|f| f.map(|f| f.into_buffer()))
+            .map(|f| f.map(image::Frame::into_buffer))
             .collect()
     } else {
         DynamicImage::from_decoder(decoder).map(|i| vec![i.into_rgba8()])