[BUG] dumps() emits an extra EOL in the EOF after inserting a node if source code ends with if-block

[webknjaz]

So basically when I parse src = '\nimport i1\nimport i2\n\nif True:\n pass\n and dump immediately, it emits the same result as the source.

But if I parse that and insert a root-level node, it adds an extra \n in the very end.

fst = RedBaron(src)
imp1, imp2 = fst.find_all('import')
imp2.insert_after(imp1)
fst.dumps()

The above returns '\nimport i1\nimport i2\nimport i1\n\nif True:\n pass\n\n'. (Note double LF in the end)

I could only reproduce this with an if-block (if-else too), but other nested constructs (like def or with-block) are not affected by this bug.

[webknjaz]

Reproducer: #191

[webknjaz]

Oh, and I originally got hit this by doing fst[23:24] = [new, nodes, list], not insert_after(), but this one looks simpler for the purposes of the demo.