Suppose I have a contact in Contacts named John Smith. John's email address is email@example.com. I've emailed him in the past, but I've never added his email to his contact details. Now, suppose I compose an email to John, then as soon as I type js, Gmail guesses that I want to email John and his full email address pops up for me. At this point, I'd like to copy his email address and add it to his contact details in Contacts.
Any way for me to do that easily?
I'm using ICS on the galaxy nexus.