Stop git from merging generated files

Author: oli-obk

.gitattributes

@@ -4,8 +4,10 @@
 *.cpp rust
 *.h rust
 *.rs rust diff=rust
-*.fixed linguist-language=Rust
-*.mir linguist-language=Rust
+*.fixed linguist-language=Rust -merge
+*.mir linguist-language=Rust -merge
+*.stderr -merge
+*.stdout -merge
 src/etc/installer/gfx/* binary
 src/vendor/** -text
 Cargo.lock linguist-generated=false