Stream delimiters breaks the Parser

[boozook]

Check out this test.

Crashing on:

...

This text should be ignored.

Parser error stack trace:

yaml.YamlException: can not read an implicit mapping pair; a colon is missed at yaml.Parser#generateError (269)
Called from yaml.Parser::throwError line 274
Called from yaml.Parser::readBlockMapping line 1489
Called from yaml.Parser::composeNode line 913
Called from yaml.Parser::readDocument line 1860
Called from yaml.Parser::parseAll line 263
Called from yaml.Parser::parse line 159
Called from yaml.Yaml::parse line 22