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

examples/file_dialog/src/main.rs

@@ -86,7 +86,7 @@ impl eframe::App for MyApp {
 
 /// Preview hovering files:
 fn preview_files_being_dropped(ctx: &egui::Context) {
-    use egui::*;
+    use egui::{Align2, Color32, Id, LayerId, Order, TextStyle};
     use std::fmt::Write as _;
 
     if !ctx.input(|i| i.raw.hovered_files.is_empty()) {