docs: Fix trailing many '+' and delimit note blocks.

[BsAtHome]

Remove most trailing '+' to force line breaks. Hard line breaks are mostly inappropriate and it should be left to paragraph formatting.
When using hard breaks in lists, then the line after the break must be indented or a warning will be issued. This was the actual cause of the messages identified in #4038.

The change caused some note/important/caution blocks to be slightly off because they were not delimited and relied on empty line delimit. These are now properly delimited so that blocks are actually identified as blocks.

This fixes #4038.

[c-morley]

I dont want this. I like my docs as they were. If there were warnings on a couple lines I will look at those, but please don't reformat my docs.
Thanks

[BsAtHome]

Forced line breaks are inappropriate formatting and actually break proper formatting when floating formatting is used (like in a browser).

However, you want it, you do it and I'll refrain from looking at your the docs.