Fix record type shorthand
Fix record type shorthand

The syntax is {c : c}, not {c = c}.

Also, replace uses of shorthand (both correct and incorrect) in
semantics rules with elaborated $[c = c].

urweb/debian-urweb,urweb/debian-urweb,urweb/debian-urweb,urweb/debian-urweb,urweb/debian-urweb