chore/ux: vague error message

[emanic]

After editing a number of SPEC files, I ran code makegen. I got the following error:

elegen folder -d specs -o codegen || exit 1
unable to decode spec yaml: yaml: line 82: mapping values are not allowed in this contextmake: *** [codegen] Error 1

It tells me the line number, but not the file.
The error was in counterreport.spec. On line 82 I had used a colon :. When I changed this to a dash -, the operation succeeded.