libyaml makes every ':' in a flow collection a value indicator, so it
mis-scans ':x', 'http://foo.com', '::vector', and 'omitted value:,', and
drops the value after an adjacent quoted or collection key. Per the spec a
':' only ends a node when followed by whitespace, end of input, or a flow
indicator, except an adjacent ':' after a JSON key (a quoted flow scalar
or a flow collection used as the key).
Gate the ':' value-indicator dispatch on that rule, tracking on the
pending simple key whether it is a JSON node (set for quoted flow scalars
and flow-collection starts). End the plain scalar at a ':' before a flow
indicator instead of rejecting it as unexpected.
Surpasses libyaml on 4ABK, 58MP, 5T43, DBG4, FRK4, HM87/00, with 9MMW
(mixing adjacent and separated keys) still correct. Port score 292 -> 298.
Mihaela Mihaljevic
ff199516ac