I'm having the same dilemma, especially because I know some workplaces don't need to know for me to do well in, but others seem to. I did perfectly fine in my last job, but I've realized lately that my other jobs in the past probably could have been improved with a mention. Unfortunately, it didn't work worth a damn in my current job (although it wasn't about mentioning it at first, since I wasn't sure then and didn't have anything to prove my diagnosis; it wasn't even my choice to bring it up in this case).
I guess I'd say my approach is more to not say it right away, and only bring it up if needed. I don't even intend to mention it directly in the future; I'm only going to say things like I may need to take notes during training, or, you know, if something comes up as an interpersonal conflict. One of my past jobs had a relaxed atmosphere, but I got flustered from time to time because the tasks weren't generally the same every time I came in, and the joking sometimes felt really hurtful more than fun — and I think some of my coworkers/supervisors just thought I was a spoilsport. Or boring. Or something, I'm not sure.