Include descritive what's new line

Author: Camilo Cota

doc/source/whatsnew/v0.18.2.txt

@@ -38,7 +38,7 @@ Other enhancements
      idx = pd.Index(["a1a2", "b1", "c1"])
      idx.str.extractall("[ab](?P<digit>\d)")
 
-- Support decimal option in PythonParser (:issue:`12933`)
+- The ``pd.read_csv()`` with engine='python' has gained support for the decimal option (:issue:`12933`)
 
 .. _whatsnew_0182.api: