implicitly imported function with same name as kwarg not recognized

Note: TimeSpans.jl exports `start`

The code:
```
stacked_area_plot!(ax, samples; start=start(density.span))
```
ExplicitImports does not seem to recognize the second `start` there as being that function. If you do `using TimeSpans: start` it will say it is an unused explicit import, even though it is used.

(example from some private code)