Add News entry

Author: pablogsal

Doc/library/re.rst

@@ -162,10 +162,10 @@ The special characters are:
 
    If you're not using a raw string to express the pattern, remember that Python
    also uses the backslash as an escape sequence in string literals; if the escape
-   sequence isn't recognized by Python's parser, it will generate a 
+   sequence isn't recognized by Python's parser, it will generate a
    :exc:`DeprecationWarning` and in the future this will become a :exc:`Syntaxerror`.
-   However, if Python would recognize the resulting sequence, the backslash should 
-   be repeated twice.  This is complicated and hard to understand, so it's highly 
+   However, if Python would recognize the resulting sequence, the backslash should
+   be repeated twice.  This is complicated and hard to understand, so it's highly
    recommended that you use raw strings for all but the simplest expressions.
 
 ``[]``

Misc/NEWS.d/next/Documentation/2018-01-21-02-26-41.bpo-32603.UDBl5w.rst

@@ -0,0 +1,3 @@
+Add comment in the re module about the fact that a backslash-character pair
+that is not a valid escape sequence now generates a DeprecationWarning.
+Patch by Pablo Galindo.