kconfig: Fix repeated include selftest expectation

kconfig: Fix repeated include selftest expectation

The err_repeated_inc test was added with an expected stderr fixture
that does not match the diagnostic printed by kconfig.

Running "make testconfig" currently fails in that test even though the
parser reports the duplicated include correctly:

  [stderr]
  Kconfig.inc1:4: error: repeated inclusion of Kconfig.inc3
  Kconfig.inc2:3: note: location of first inclusion of Kconfig.inc3

The fixture expects "Repeated" and "Location" with capital letters, but
the diagnostic emitted by scripts/kconfig/util.c uses lowercase words.
Update the fixture to match the real message.

Fixes: 102d712ded3e ("kconfig: Error out on duplicated kconfig inclusion")
Signed-off-by: Zhou Yuhang <zhouyuhang@kylinos.cn>
Tested-by: Nicolas Schier <nsc@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20260520070800.2265479-1-zhouyuhang1010@163.com
Signed-off-by: Nicolas Schier <nsc@kernel.org>