v1.4.3

Add validation to detect common typos where assignment operators are reversed. The formatter now generates helpful warnings (see #63):

• =? (should be ?=) for conditional assignment
• =: (should be :=) for immediate assignment
• =+ (should be +=) for append assignment

Resolves issue where suffix rules and file targets were incorrectly suggested as phony targets (see #62). Includes:

• Fix PhonyAnalyzer to detect 'target name as last argument' pattern (e.g., cp input.txt clean)
• Update phony detection to properly exclude suffix rules (.a.b:) and file targets (foo.b:)
• Add comprehensive suffix validation with duplicate detection and pattern warnings
• Add extensive test coverage for new validation features
• Fix .POSIX and other special targets being incorrectly suggested as phony