Added versionadded tag and removed unused code

Author: amilbourne

pandas/_libs/testing.pyx

@@ -92,6 +92,9 @@ cpdef assert_almost_equal(a, b,
     index : str, default None
         Specify shared index of objects being compared, internally used to
         show appropriate assertion message
+
+        .. versionadded:: 1.1.0
+
     """
     cdef:
         int decimal

pandas/_testing.py

@@ -908,9 +908,6 @@ def raise_assert_detail(obj, message, left, right, diff=None, index=None):
     elif is_categorical_dtype(right):
         right = repr(right)
 
-    if isinstance(index, np.ndarray):
-        index = pprint_thing(index)
-
     msg += f"""
 [left]:  {left}
 [right]: {right}"""