refactor(developer): reorganize messages for adding details

Moved the ERROR_Message line above the Error_Message line for every
message in the compiler message files, as it makes the grouping clearer
once we start adding message details. For example, see the start of the
KmnCompilerMessages class.

Also wraps potentially-undefined parameters to the messages with a new
function `def`, shorthand for `CompilerMessageDef`, which converts the
parameter to '<param>' if it is undefined, which is helpful for
documentation.