This fixes the example "Example 5.13 Escaped Characters" from the YAML
specification.
The example demands that `\_` is being translated to unicode `\u00a0`.
The unicode codepoint `\u00A0` encoded for utf-8 in hex is `\xC2\xA0`.
Fixing this test case will cause the unit test to not pass, since the
codepoint `\u00A0` is not handled correctly.
(Failing unittest is expected).
