Revisit `Markd::Options` class

[devnote-dev]

I think that there could be some changes/improvements to the current Options class:

• Removing unimplemented options: given that they're not used, there's no actual reason to have them in the class – having a TODO comment or similar in place would be better for whomever wants to implement them
• Removing time: I understand the purpose but this is really something that users could implement themselves if they wanted that information, and it's relatively easy to do
• Replace safe: I like this option, but it is quite restricting – if you wanted to allow table HTML and nothing else, there would be no way to do that without performing string manipulation post-rendering. I think it would be better to change this into something like sanitize which gives you options on what HTML elements you want to allow, there is a sanitize shard that would be great for this
• Rename prettyprint: (this one isn't important, but pretty_print makes so much more sense here lol)

WDYT?

[ralsina]

Is there a consensus about any of this being needed?

• I don't mind unimplemented options (and I don't think there are any anymore?)
• Removing time ... it costs nothing to keep it.
• Replace safe ... we have tagfilter
• prettyprint ... I don't really care :-)

[nobodywasishere]

toc is still unimplemented, but I'm fine leaving it as-is for now. I've just added some documentation that it isn't used currently.

Integration with the sanitize shard is something I've done before for the docs generator, but don't know if that work should be upstreamed given it'd require adding a dependency on said shard.

I'm fine leaving time and prettyprint as-is personally.

Related: #97

[devnote-dev]

Please bear in mind this is a 2-year old issue and I haven't been following the development of this shard to update it accordingly.

time provides no versatility to the user, and worse, it prints to stdout out without choice, which is very annoying to deal with in CLI applications.

tagfilter isn't necessarily an improvement over safe, nor does it address the issue in my initial comment.

I'm not strongly opposed to prettyprint, but it would conform to the existing naming convention in the standard library.