Spec/implementation harmony.

I did two things here: (1) made the lettering for formats 35c and 35ms
match how things are actually implemented; and (2) formally defined
formats 35mi and 3rmi, to correspond to the inline linked formats
actually used in our current implementation.

In neither case does this change the meaning of the spec in any
substantive way. The first case is just about labels, and the second
case is just about (from the standpoint of the spec) a suggestion.

Change-Id: I6a6226a8cdd82ae4dcc43d342a9e9b98582cefd7