Remove wildcard imports (#5018)

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I removed (I hope so) all wildcard imports I found.

For me on my pc this improved the build time:
- for egui -5s
- for eframe -12s

* [x] I have followed the instructions in the PR template

crates/egui_demo_app/src/apps/fractal_clock.rs

@@ -1,4 +1,9 @@
-use egui::{containers::*, widgets::*, *};
+use egui::{
+    containers::{CollapsingHeader, Frame},
+    emath, pos2,
+    widgets::Slider,
+    Color32, Painter, Pos2, Rect, Shape, Stroke, Ui, Vec2,
+};
 use std::f32::consts::TAU;
 
 #[derive(PartialEq)]

crates/egui_demo_app/src/frame_history.rs

@@ -53,7 +53,7 @@ impl FrameHistory {
     }
 
     fn graph(&mut self, ui: &mut egui::Ui) -> egui::Response {
-        use egui::*;
+        use egui::{emath, epaint, pos2, vec2, Pos2, Rect, Sense, Shape, Stroke, TextStyle};
 
         ui.label("egui CPU usage history");
 

crates/egui_demo_app/src/wrap_app.rs

@@ -428,7 +428,7 @@ impl WrapApp {
     }
 
     fn ui_file_drag_and_drop(&mut self, ctx: &egui::Context) {
-        use egui::*;
+        use egui::{Align2, Color32, Id, LayerId, Order, TextStyle};
         use std::fmt::Write as _;
 
         // Preview hovering files: