Revert "Fixed a typo in the HTMLParser.feed docstrings" (#1771)

* Revert "Fixed a typo in the HTMLParser.feed docstrings. The docstring started with an 'r', like a The docstring was correct. I read the patch in opposite direction, as *adding* the "r" prefix.
This reverts commit 5ba185039f1bd465d3f82531324fd3fe1ee42f0c.
diff --git a/Lib/html/parser.py b/Lib/html/parser.py
index 9597948..ef869bc 100644
--- a/Lib/html/parser.py
+++ b/Lib/html/parser.py
@@ -102,7 +102,7 @@
         _markupbase.ParserBase.reset(self)
 
     def feed(self, data):
-        """Feed data to the parser.
+        r"""Feed data to the parser.
 
         Call this as often as you want, with as little or as much text
         as you want (may include '\n').