Problem:    Available encryption methods are not strong enough.
Solution:   Add initial support for xchaha20. (Christian Brabandt,
            closes #8394)

Problem:    Missing test file.
Solution:   Add samples/test000. (Christian Brabandt)

Problem:    Not all parts of the quickfix code are tested.
Solution:   Add more tests. (Yegappan Lakshmanan)

Problem:    Quickfix doesn't handle long lines well, they are split.
Solution:   Drop characters after a limit. (Anton Lindqvist)

Problem:    With some regexp patterns the NFA engine uses many states and
            becomes very slow.  To the user it looks like Vim freezes.
Solution:   When the number of states reaches a limit fall back to the old
            engine. (Christian Brabandt)