About [[Blockly:Code.badXml/ia]]

I spoke to my tech lead, and he said:

• You're right.
• The reason we have OK/Cancel is we're using the default dialog window.
• This message is not frequently seen.

For now, I will rephrase the English-language message to make it clearer what the user should do. It may take a few days for the change to show up in translatewiki.

Thank you.