Preview length improvements

[schultzcole]

It would be handy to be able to configure the journal previews more finely. In particular, it'd be nice to be able to adjust the max length of HTML previews (though I understand why it isn't that way right now). I think it would be great if it could show a preview of the text up to the first heading.

For instance if I have a description of a settlement, I could start it off with a short summary:

"Heston is a very nice town nestled in the Piramor valley, surrounded by groves of peach trees"

Then have a heading (or maybe horizontal rule could work) followed by a more detailed description.

Ideally I could set it to show only the summary paragraph prior to the first heading.

[eclarke12]

The HTML preview length is configurable in Module Settings, however more complicated preview clipping isn't necessarily in scope at the moment.

One idea I have is to cut off the preview after the first closed tag, however I need to investigate the effort and feasibility of this.