parser_util: drop injected tokens in `parse_someting`

Since injected tokens have a false location, highlight.nit had a bad
behavior when trying to color them.
Thez should not survive `parse_something`.

Fixes #451
Signed-off-by: Jean Privat <jean@pryen.org>
tests: update test_markdown and test_parser

Signed-off-by: Jean Privat <jean@pryen.org>
Merge: parser_util: drop injected tokens in `parse_someting`

Since injected tokens have a false location, highlight.nit had a bad
behavior when trying to color them.
Thez should not survive `parse_something`.

Fixes #451

Pull-Request: #453
Reviewed-by: Alexandre Terrasa <alexandre@moz-code.org>