omission of FAST or SLOW in a clock signal SET line should be an error, not a warning #37
Description
When a line like:
`SET SIG TO VOLTAGE;"
is written where SIG is a designator for a clock output, wdl emits a warning because it doesn't know which slew rate to use ("*** For clock waveforms, 'FAST' or 'SLOW' needs to be specified ***").
HOWEVER, compilation continues and no line is emitted whatsoever. I.e. the compilation succeeds but fails to express the author intent. In my book this is a textbook case of a thing that should halt compilation rather than continue.