Add a test for json:"-," field

Author: tsuzu

Diff for: pkg/analysis/commentstart/testdata/src/a/a.go

@@ -6,6 +6,7 @@ type CommentStartTestStruct struct {
 	InlineJSONTag string `json:",inline"`
 	NoComment     string `json:"noComment"` // want "field NoComment is missing godoc comment"
 	Ignored       string `json:"-"`
+	Hyphen        string `json:"-,"` // want "field Hyphen is missing godoc comment"
 
 	// IncorrectStartComment is a field with an incorrect start to the comment. // want "godoc for field IncorrectStartComment should start with 'incorrectStartComment ...'"
 	IncorrectStartComment string `json:"incorrectStartComment"`

Diff for: pkg/analysis/commentstart/testdata/src/a/a.go.golden

@@ -6,6 +6,7 @@ type CommentStartTestStruct struct {
 	InlineJSONTag string `json:",inline"`
 	NoComment     string `json:"noComment"` // want "field NoComment is missing godoc comment"
 	Ignored       string `json:"-"`
+	Hyphen        string `json:"-,"` // want "field Hyphen is missing godoc comment"
 
 	// incorrectStartComment is a field with an incorrect start to the comment. // want "godoc for field IncorrectStartComment should start with 'incorrectStartComment ...'"
 	IncorrectStartComment string `json:"incorrectStartComment"`