Fix incorrect doctest output

the ValueError did actually not make sense.

src/sage/rings/padics/padic_valuation.py

@@ -724,9 +724,8 @@ def extensions(self, ring):
             sage: R.<x> = QQ[]
             sage: L.<a> = NumberField(x^4 + 2*x^3 + 2*x^2 + 8)
             sage: QQ.valuation(2).extensions(L)
-            Traceback (most recent call last):
-            ...
-            ValueError: The valuation [ Gauss valuation induced by 2-adic valuation, v(x) = 1/2 ] does not approximate a unique extension of 2-adic valuation with respect to x^4 + 2*x^3 + 2*x^2 + 8
+            [[ 2-adic valuation, v(x + 2) = 3/2 ]-adic valuation,
+             [ 2-adic valuation, v(x) = 1/2 ]-adic valuation]
 
         A case where the extension was incorrect at some point::