refactor(output): share the JSON, created-resource and batch tails

Mutations end with a.jsonResult or a.created instead of hand-rolled
--json branches, the two identical jsonResult/writeMutationJSON helpers
become one, and writeBatchJSON checks --json itself so batch commands
share one tail.

Signed-off-by: bircni <bircni@icloud.com>

internal/app/issue_attachments.go

@@ -111,11 +111,8 @@ $ tea %[1]s attachment upload %[2]s screenshot.png --name before.png`, words.gro
 		if err != nil {
 			return err
 		}
-		if a.options.json != "" {
-			return a.writeJSON(cmd, item)
-		}
 		a.done(cmd, "Uploaded %s (%s) to %s#%d", item.Name, terminal.Bytes(item.Size), t.Repo, n)
-		return a.printURL(cmd, item.URL)
+		return a.created(cmd, item, item.URL)
 	}}
 	upload.Flags().StringVar(&uploadName, "name", "", "File `name` of the attachment (default: the local file name)")
 
@@ -132,11 +129,8 @@ $ tea %[1]s attachment upload %[2]s screenshot.png --name before.png`, words.gro
 		if err != nil {
 			return err
 		}
-		if a.options.json != "" {
-			return a.writeJSON(cmd, item)
-		}
 		a.done(cmd, "Renamed %s", attachmentName(t, n, item))
-		return nil
+		return a.jsonResult(cmd, item)
 	}}
 	edit.Flags().StringVar(&newName, "name", "", "New file `name`")