Make generated files appear as generated (home-assistant#134991)

Author: KapJI

.gitattributes

@@ -11,3 +11,14 @@
 *.pcm binary
 
 Dockerfile.dev linguist-language=Dockerfile
+
+# Generated files
+CODEOWNERS linguist-generated=true
+Dockerfile linguist-generated=true
+homeassistant/generated/*.py linguist-generated=true
+mypy.ini linguist-generated=true
+requirements.txt linguist-generated=true
+requirements_all.txt linguist-generated=true
+requirements_test_all.txt linguist-generated=true
+requirements_test_pre_commit.txt linguist-generated=true
+script/hassfest/docker/Dockerfile linguist-generated=true