feat: Add support for function variants and fixups in Mach-O file parsing

- Introduced FunctionVariants and FunctionVariantFixups load commands.
- Implemented methods to retrieve and parse function variants and fixups data.
- Enhanced symbol resolution for function variants based on CPU features.
- Added new types and constants for ARM64 and x86_64 CPU feature flags.
- Updated stringer generation for new types and commands.
- Modified the Enrich method to include function variants and fixups parsing.
- Improved error handling for missing load commands.

Author: blacktop

Makefile

@@ -46,6 +46,14 @@ destroy: ## Remove release from the VERSION
 	git tag -d ${VERSION}
 	git push origin :refs/tags/${VERSION}
 
+.PHONY: fmt
+fmt: ## Format code
+	@echo " > Formatting code"
+	@gofmt -w -r 'interface{} -> any' .
+	@goimports -w .
+	@gofmt -w -s .
+	@go mod tidy	
+
 # Absolutely awesome: http://marmelab.com/blog/2016/02/29/auto-documented-makefile.html
 help:
 	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'