bpo-18374: fix wrong col_offset of some ast.BinOp instances (GH-14607)

Nested BinOp instances (e.g. a+b+c) had a wrong col_offset for the
second BinOp (e.g. 2 instead of 0 in the example). Fix it by using the
correct st node to copy the line and col_offset from in ast.c.
diff --git a/Misc/ACKS b/Misc/ACKS
index 36fe727..d916c45 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -178,6 +178,7 @@
 David Bolen
 Wouter Bolsterlee
 Gawain Bolton
+Carl Friedrich Bolz-Tereick
 Forest Bond
 Gregory Bond
 Médéric Boquien