BUG/FEA: line number tracking for nested functions loses interior coordinates

[daz10000]

With the multiple source position tracking feature, the call to functionThree in the source below records the line 4 final position and the call on line but misses line 15 and line 8. There is a test to assert the number of coordinates is 4 TestNestedFunctionExpansionHasThreeSources which is currently marked ignore. This test should ideally pass (and have its <Ignore> tag removed)

#refgenome cenpk
#platform stitch

let fun1(up,down) = // line 3 (zero numbered)
&up ; &down // line 4
end

let funTwo(gene) = // line 7 
fun1(&gene,&gene) // line 8
end

fun1(uADH1,dADH1) // line 11
funTwo(uADH4) // line 12

let functionThree() = // line 14
 funTwo(uADH7) // line 15
end


         functionThree() // line 19