Minor logger improovments (temporalio#1495)

Move WithLogger interface to other logger interfaces

log/logger.go

@@ -39,4 +39,10 @@ type (
 	WithSkipCallers interface {
 		WithCallerSkip(int) Logger
 	}
+
+	// WithLogger is an optional interface that prepend every log entry with keyvals.
+	// This call must not mutate the original logger.
+	WithLogger interface {
+		With(keyvals ...interface{}) Logger
+	}
 )

log/with_logger.go

@@ -24,11 +24,6 @@
 
 package log
 
-// WithLogger is an interface that prepend every log entry with keyvals.
-type WithLogger interface {
-	With(keyvals ...interface{}) Logger
-}
-
 // With creates a child Logger that includes the supplied key-value pairs in each log entry. It does this by
 // using the supplied logger if it implements WithLogger; otherwise, it does so by intercepting every log call.
 func With(logger Logger, keyvals ...interface{}) Logger {
@@ -57,7 +52,7 @@ type withLogger struct {
 }
 
 func newWithLogger(logger Logger, keyvals ...interface{}) *withLogger {
-	return &withLogger{logger: logger, keyvals: keyvals}
+	return &withLogger{logger: Skip(logger, 1), keyvals: keyvals}
 }
 
 func (l *withLogger) prependKeyvals(keyvals []interface{}) []interface{} {