LB, I’m not saying it’s wrong. I’m just pointing out that it may be inappropriate. Like shortening Moishe to Moishy is fine for my nephew who is 6 or 16 or even 26. But you wouldn’t call your Rov, Rav Moishy as an example. Yerushalayim, is a Holy City, and our language should reflect that.
(Having said that, my Rov is known by a shortened form Yiddish name. Let’s say for arguments sake, Reb Leibel. Some people in this town call him Reb Leibel, but I feel very uncomfortable. They may have known him for a very long time. On Purim, my sister was saying, “We’re going to Reb Leibel now. Are you coming?…” etc. It did annoy me. But, her father in law has known him for a long time, so possibly in their family it’s ok.)