Trac #32964: fix failing doctest in functions.orthogonal_polys.

One of the examples in this module is expecting a doctest warning, but
that warning is only emitted the first time it happens. When testing
with

  sage -t --file-iterations=2

the warning does not appear in the second pass, and the test (that is
expecting it) fails. This commit adds some more "..." to support both
possible outcomes.

Author: orlitzky

src/sage/functions/orthogonal_polys.py

@@ -495,8 +495,7 @@ def _eval_(self, n, x):
             sage: chebyshev_T(5,Qp(3)(2))
             2 + 3^2 + 3^3 + 3^4 + 3^5 + O(3^20)
             sage: chebyshev_T(100001/2, 2)
-            doctest:...: RuntimeWarning: mpmath failed, keeping expression unevaluated
-            chebyshev_T(100001/2, 2)
+            ...chebyshev_T(100001/2, 2)
             sage: chebyshev_U._eval_(1.5, Mod(8,9)) is None
             True
         """