add comment for mergetool usage, ignore mergetool artifacts

Signed-off-by: ahuston-0 <aliceghuston@gmail.com>

.gitignore

@@ -9,7 +9,11 @@ result
 result-*
 
 # If you run nix develop it will generate pre-commit hooks using the python library precommit (see https://github.com/RAD-Development/nix-dotfiles/blob/main/flake.nix#L65)
-.pre-commit-config.yaml
+**/.pre-commit-config.yaml
+
+# omits sops-mergetool artifacts
+**/*.yaml.orig
+**/*.yml.orig
 
 # allows test file in reopsitory
 test.*