add simple descriptions for swagger validate (#4087)

* Partial fix for #4010

Swagger needs a comment line above each swagger:response comment -- it
uses these to populate the description: fields.  Adding minimal text
for now on the way to getting swagger validate to pass.  Many standard
swagger client libraries will not work at all with gitea until validate
passes, so prioritizing that over better descriptions for now.

Signed-off-by: Steve Traugott <stevegt@t7a.org>

routers/api/v1/swagger/user.go

@@ -8,18 +8,21 @@ import (
 	api "code.gitea.io/sdk/gitea"
 )
 
+// User
 // swagger:response User
 type swaggerResponseUser struct {
 	// in:body
 	Body api.User `json:"body"`
 }
 
+// UserList
 // swagger:response UserList
 type swaggerResponseUserList struct {
 	// in:body
 	Body []api.User `json:"body"`
 }
 
+// EmailList
 // swagger:response EmailList
 type swaggerResponseEmailList struct {
 	// in:body