Automated Resyntax fixes

[resyntax-ci[bot]]

Resyntax fixed 20 issues in 5 files.

• Fixed 12 occurrences of let-to-define
• Fixed 2 occurrences of comparison-of-difference-and-zero-to-direct-comparison
• Fixed 1 occurrence of if-let-to-cond
• Fixed 1 occurrence of send-chain-to-send+
• Fixed 1 occurrence of nested-if-to-cond
• Fixed 1 occurrence of map-to-for
• Fixed 1 occurrence of hash-ref-with-constant-lambda-to-hash-ref-without-lambda
• Fixed 1 occurrence of when-expression-in-for-loop-to-when-keyword