CWL parameter references: detect attempts to use parameters not in the current namespace and suggest a fix

For example: users might try to access workflow level inputs when doing step level `valueFrom` parameter references or while using the `when` conditional execution directive.

We should detect this and present a targeted error message. Ideally we would even show a small source code diff (with correct line numbers) to add that workflow level inputs parameter to the step level `in` section so it would be visible in the `$(inputs)` object.