better warning for assigning arg names to non-function types

Something like:

```
@param {can.compute.asyncComputer} computed(newVal)
```

only logs:

```
"WARNING! "+obj.types[0].name+" does not appear to be a function."+
" If it is a typedef, you can not specify the params to the typedef. "
```

This should let someone know where this is happening. Perhaps throwing an error that will report.

Reproduce the warning with the documented `@param {can.compute.asyncComputer} computed(newVal)` example, then locate the code that emits the non-function warning. Determine how the warning can identify where the invalid parameter assignment occurs, and confirm with maintainers whether reporting or throwing is expected before defining done.

Written by the indexing model from the issue text.