doc updates, and relabel ReportMethod

in the Logrus context it's the caller, so use that internally.  Label
stays as 'method' since in the context of the log event that seems more
correct.

logrus_test.go

@@ -56,11 +56,11 @@ func LogAndAssertText(t *testing.T, log func(*Logger), assertions func(fields ma
 	assertions(fields)
 }
 
-// TestReportMethod verifies that when ReportMethod is set, the 'method' field
+// TestReportCaller verifies that when ReportCaller is set, the 'method' field
 // is added, and when it is unset it is not set or modified
-func TestReportMethod(t *testing.T) {
+func TestReportCaller(t *testing.T) {
 	LogAndAssertJSON(t, func(log *Logger) {
-		SetReportMethod(false)
+		SetReportCaller(false)
 		log.Print("testNoCaller")
 	}, func(fields Fields) {
 		assert.Equal(t, fields["msg"], "testNoCaller")
@@ -69,7 +69,7 @@ func TestReportMethod(t *testing.T) {
 	})
 
 	LogAndAssertJSON(t, func(log *Logger) {
-		SetReportMethod(true)
+		SetReportCaller(true)
 		log.Print("testWithCaller")
 	}, func(fields Fields) {
 		assert.Equal(t, fields["msg"], "testWithCaller")
@@ -77,7 +77,7 @@ func TestReportMethod(t *testing.T) {
 		assert.Equal(t, fields["method"], "testing.tRunner")
 	})
 
-	SetReportMethod(false) // return to default value
+	SetReportCaller(false) // return to default value
 }
 
 func TestPrint(t *testing.T) {
@@ -269,7 +269,7 @@ func TestNestedLoggingReportsCorrectCaller(t *testing.T) {
 	var buffer bytes.Buffer
 	var fields Fields
 
-	SetReportMethod(true)
+	SetReportCaller(true)
 	logger := New()
 	logger.Out = &buffer
 	logger.Formatter = new(JSONFormatter)
@@ -311,7 +311,7 @@ func TestNestedLoggingReportsCorrectCaller(t *testing.T) {
 	assert.Nil(t, fields["fields.msg"], "should not have prefixed previous `msg` entry")
 	assert.Equal(t, "testing.tRunner", fields["method"])
 
-	SetReportMethod(false) // return to default value
+	SetReportCaller(false) // return to default value
 }
 
 func TestConvertLevelToString(t *testing.T) {