Enable the clippy::std_instead_of_core lint (#8394)

Prefer `core::` over `std::` where either work

* Part of https://github.com/emilk/egui/issues/5735

crates/egui_extras/src/datepicker/button.rs

@@ -1,7 +1,7 @@
 use super::popup::DatePickerPopup;
+use core::ops::RangeInclusive;
 use egui::{Area, Button, Frame, InnerResponse, Key, Order, RichText, Ui, Widget};
 use jiff::civil::Date;
-use std::ops::RangeInclusive;
 
 #[derive(Default, Clone)]
 #[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]

crates/egui_extras/src/datepicker/mod.rs

@@ -26,7 +26,7 @@ fn month_data(year: i16, month: i8) -> Vec<Week> {
         if start.weekday() == Weekday::Sunday {
             weeks.push(Week {
                 number: ISOWeekDate::from(start).week() as u8,
-                days: std::mem::take(&mut week),
+                days: core::mem::take(&mut week),
             });
         }
         start = start.tomorrow().unwrap();

crates/egui_extras/src/datepicker/popup.rs

@@ -32,7 +32,7 @@ pub(crate) struct DatePickerPopup<'a> {
     pub calendar: bool,
     pub calendar_week: bool,
     pub highlight_weekends: bool,
-    pub start_end_years: Option<std::ops::RangeInclusive<i16>>,
+    pub start_end_years: Option<core::ops::RangeInclusive<i16>>,
     pub reverse_years: bool,
     pub year_scroll_to: Option<i16>,
 }

crates/egui_extras/src/loaders/file_loader.rs

@@ -1,9 +1,10 @@
 use ahash::HashMap;
+use core::task::Poll;
 use egui::{
     load::{Bytes, BytesLoadResult, BytesLoader, BytesPoll, LoadError},
     mutex::Mutex,
 };
-use std::{path::PathBuf, sync::Arc, task::Poll, thread};
+use std::{path::PathBuf, sync::Arc, thread};
 
 #[derive(Clone)]
 struct File {

crates/egui_extras/src/loaders/gif_loader.rs

@@ -1,11 +1,12 @@
 use ahash::HashMap;
+use core::{mem::size_of, time::Duration};
 use egui::{
     ColorImage, FrameDurations, Id, decode_animated_image_uri, has_gif_magic_header,
     load::{BytesPoll, ImageLoadResult, ImageLoader, ImagePoll, LoadError, SizeHint},
     mutex::Mutex,
 };
 use image::AnimationDecoder as _;
-use std::{io::Cursor, mem::size_of, sync::Arc, time::Duration};
+use std::{io::Cursor, sync::Arc};
 
 /// Array of Frames and the duration for how long each frame should be shown
 #[derive(Debug, Clone)]

crates/egui_extras/src/loaders/http_loader.rs

@@ -1,9 +1,10 @@
 use ahash::HashMap;
+use core::task::Poll;
 use egui::{
     load::{Bytes, BytesLoadResult, BytesLoader, BytesPoll, LoadError},
     mutex::Mutex,
 };
-use std::{sync::Arc, task::Poll};
+use std::sync::Arc;
 
 #[derive(Clone)]
 struct File {

crates/egui_extras/src/loaders/image_loader.rs

@@ -1,11 +1,12 @@
 use ahash::HashMap;
+use core::{mem::size_of, task::Poll};
 use egui::{
     ColorImage, decode_animated_image_uri,
     load::{Bytes, BytesPoll, ImageLoadResult, ImageLoader, ImagePoll, LoadError, SizeHint},
     mutex::Mutex,
 };
 use image::ImageFormat;
-use std::{mem::size_of, path::Path, sync::Arc, task::Poll};
+use std::{path::Path, sync::Arc};
 
 #[cfg(not(target_arch = "wasm32"))]
 use std::thread;
@@ -146,7 +147,7 @@ impl ImageLoader for ImageCrateLoader {
                 .map(Arc::new)
                 .map_err(|err| err.to_string());
             log::trace!("finished loading {uri:?}");
-            cache_lock.insert(uri.into(), std::task::Poll::Ready(result.clone()));
+            cache_lock.insert(uri.into(), core::task::Poll::Ready(result.clone()));
             match result {
                 Ok(image) => Ok(ImagePoll::Ready { image }),
                 Err(err) => Err(LoadError::Loading(err)),

crates/egui_extras/src/loaders/svg_loader.rs

@@ -1,4 +1,5 @@
-use std::{mem::size_of, sync::Arc};
+use core::mem::size_of;
+use std::sync::Arc;
 
 use ahash::HashMap;
 

crates/egui_extras/src/loaders/webp_loader.rs

@@ -1,11 +1,12 @@
 use ahash::HashMap;
+use core::{mem::size_of, time::Duration};
 use egui::{
     ColorImage, FrameDurations, Id, decode_animated_image_uri, has_webp_header,
     load::{BytesPoll, ImageLoadResult, ImageLoader, ImagePoll, LoadError, SizeHint},
     mutex::Mutex,
 };
 use image::{AnimationDecoder as _, ColorType, ImageDecoder as _, Rgba, codecs::webp::WebPDecoder};
-use std::{io::Cursor, mem::size_of, sync::Arc, time::Duration};
+use std::{io::Cursor, sync::Arc};
 
 #[derive(Clone)]
 enum WebP {

crates/egui_extras/src/syntax_highlighting.rs

@@ -514,9 +514,9 @@ struct HighlightSettings<'a>(&'a SyntectSettings);
 #[derive(Copy, Clone)]
 struct HighlightSettings<'a>(&'a ());
 
-impl std::hash::Hash for HighlightSettings<'_> {
-    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
-        std::ptr::hash(self.0, state);
+impl core::hash::Hash for HighlightSettings<'_> {
+    fn hash<H: core::hash::Hasher>(&self, state: &mut H) {
+        core::ptr::hash(self.0, state);
     }
 }