v5.3.7

v5.3.7 — Python false-positive fixes (#66, #67)

string literals/comments — now AST-based (ast.Compare + Is/IsNot against a
real literal) instead of a raw-source regex.
exclusion is anchored as a keyword_argument selector so multi-line and
single-line calls with encoding= are correctly excluded (and binary-mode
opens too). Both fixed with buggy+clean fixtures pinning each direction.