Replace #[allow attributes with expect (#7796)

We do have `clippy::allow_attributes` turned on, but it doesn't seem to
work properly

crates/epaint/src/text/font.rs

@@ -1,4 +1,4 @@
-#![allow(clippy::mem_forget)]
+#![expect(clippy::mem_forget)]
 
 use emath::{GuiRounding as _, OrderedFloat, Vec2, vec2};
 use self_cell::self_cell;

crates/epaint/src/text/text_layout_types.rs

@@ -1,6 +1,3 @@
-#![allow(clippy::derived_hash_with_manual_eq)] // We need to impl Hash for f32, but we don't implement Eq, which is fine
-#![allow(clippy::wrong_self_convention)] // We use `from_` to indicate conversion direction. It's non-diomatic, but makes sense in this context.
-
 use std::ops::Range;
 use std::sync::Arc;