correct the handling of cdot in raw string

Author: kiwifb

src/sage/rings/polynomial/infinite_polynomial_element.py

@@ -1294,7 +1294,7 @@ def stretch(self, k):
 
         OUTPUT:
 
-        Replace `v_n` with `v_{n\\cdot k}` for all generators `v_\ast` occurring in self.
+        Replace `v_n` with `v_{n\cdot k}` for all generators `v_\ast` occurring in self.
 
         EXAMPLES::