The standard-library structured logger `log/slog` (Go 1.21+) was not
modeled, so `go/log-injection` and `go/clear-text-logging` were blind to
any code that logs through it.
Model its logging functions and `*slog.Logger` methods — `Debug`, `Info`,
`Warn`, `Error`, their `Context` variants, and `Log`/`LogAttrs` — as
`log-injection` sinks (the kind that feeds `LoggerCall`, powering both
queries). Adds `log/slog` cases to the `LoggerCall` library test.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
