Improvements .gitignore (#15798)

# Objective

I tried to improve gitignore. I am not a programming expert yet, so I
don't know all the junk files. If someone provides me with a list of
other files, can you point me to it below? I also tried to sort them
logically, hope it works.

> This is also my first PR in the history of this engine. and I'm very
happy 😄

.gitignore

@@ -1,26 +1,33 @@
+# Rust build artifacts
 /target
 crates/*/target
 **/*.rs.bk
+/benches/target
+/tools/compile_fail_utils/target
+
+# Cargo
 Cargo.lock
 .cargo/config
 .cargo/config.toml
+
+# IDE files
 /.idea
 /.vscode
 .zed
-/benches/target
-/tools/compile_fail_utils/target
 dxcompiler.dll
 dxil.dll
 
-# Generated by "examples/scene/scene.rs"
-assets/scenes/load_scene_example-new.scn.ron
-
-# Generated by "examples/window/screenshot.rs"
-**/screenshot-*.png
-
+# Bevy Assets
 assets/**/*.meta
 crates/bevy_asset/imported_assets
 imported_assets
 
+# Bevy Examples
 example_showcase_config.ron
 example-showcase-reports/
+
+# Generated by "examples/scene/scene.rs"
+assets/scenes/load_scene_example-new.scn.ron
+
+# Generated by "examples/window/screenshot.rs"
+**/screenshot-*.png