refactor Hledger.Write.Html etc

[simonmichael]

• dev: rename printHtml -> styledTableHtml
• dev: refactor Hledger.Write.Html etc, reducing Lucid references

[simonmichael]

This is FYI @thielema:

So that I could troubleshoot hledger's HTML output or inspect report diffs, I attempted to "quickly" add newlines to it. Instead I did some refactoring and research in that direction. Here's the new doc for Hledger.Write.Html:

HTML writing helpers.
This module would ideally hide the details of which HTML library is used, but it doesn't yet.

Currently hledger-web uses blaze-html, but hledger CLI reports use lucid.
lucid has a more usable API than blaze-html (https://chrisdone.com/posts/lucid).
lucid2's is even better.
Unfortunately lucid* can not render multi-line or indented text.
We want this so that humans can read and troubleshoot our HTML output.
So a transition to blaze-html may be coming.

It seems to me that moving hledger to blaze-html is forced here, even though its API is ugly. At least until/unless chrisdone/lucid#161 happens. Let me know if you agree.