doc overhaul step 3: update userguide #2111
those that don't need to put into a dedicated file are now inside the miscellaneous.txt
There's a lot going on here. I'm going to accept this without reviewing it thoroughly.
Don't feel obliged to create a changelog for each PR. An end-user is not going to care that there were multiple phases of a doc overhaul. I'll likely consolidate these when we get around to merging the changes.
In #1738, some substantial changes were made to the docs. I hope those don't cause difficulty in conflicts. Please try to incorporate those changes into yours.