ConnectedText http://www.connectedtext.com/screenshots.php
It allows you to store massive amounts of free text + structured texts + attributes and properties for each topic. You can connect everything as densely as you want, search it inline or in dedicated queries, or simply list all members of any given property/ attribute/ category etc.

No database knowledge necessary. You create all these structures on the fly, while typing yr text. The rendered text will format according to your CSS stlye sheet settings. You quickly switch between edit view and rendered view via shortcut or toolbar button. Shortcuts and toolbars can be customized.

You can easily link to, cross-reference, and also include topics and parts of topics. You can set up dynamic search pages or call up a search dialog. Tons of other features you may find useful for what you have in mind.

I've been using ConnectedText for over 10 years. My largest project has <5000 topics, some of them contain dozens of subheadings and tons of text. No performance problems at all.

It is not free. The installed version sells for 40 USD; an additional USB-option will cost you 20 USD on top.

The latest version is from 2015, however. Seems like development has come to a halt, I am afraid.

Waaay too late - CONGRATULATIONS all the more, though 

....except, that those two items are hard-coded...  (I add them statically; never imagined that anyone would want to remove them)
Okay, Ill fix that in the next version.

-BGM (March 08, 2019, 05:04 PM)

Thank you. I really appreciate it. Like you said, users who want to keep those 2 commands in their customized menus can easily do that - by adding the respective IDs. But for those who don't need it, it would free up valuable space.  :Thmbsup:

Your help docs are very clear, btw. In fact, one of the best help files I've come across. With numerous examples and detailed explanations. No complaints whatsoever.
When putting it into practice, I run into some inconistencies. According to the help file:

The ... in the Menu titles indicates that the command uses a dialogue box to gather user information - you should hold the modifier key WHEN you push the Accept button in the dialogue.

This is not the way it works with Trim N Characters (713). It requires holding the modifier key BEFORE calling up the dialog. Once you're in the dialog box, it's too late, clicking the Accept button with a modifier key has no effect.

Actually, I see "Trim N Characters" as a line command, I cannot imagine a usage scenario other than in multi-line situations. I mean, who uses that command on the first line only? Much easier to simply delete the chars up front than going through the motions with menu and dialog box. So imo, the command should work on individual lines by default, just like Renumber Lines (725), but maybe that's just me.

It were nice to have an "Add N Characters" command as well, especially for markdown docs, to add asterisks for bullets or letters and numbers for lists:
 *
 a.
 1.