Issue #17225: JSON decoder now counts columns in the first line starting
with 1, as in other lines.
diff --git a/Lib/json/decoder.py b/Lib/json/decoder.py
index 7e2c68c..dc8916c 100644
--- a/Lib/json/decoder.py
+++ b/Lib/json/decoder.py
@@ -27,7 +27,7 @@
 def linecol(doc, pos):
     lineno = doc.count('\n', 0, pos) + 1
     if lineno == 1:
-        colno = pos
+        colno = pos + 1
     else:
         colno = pos - doc.rindex('\n', 0, pos)
     return lineno, colno