fix(styling): Allow for spacing between paragraphs of non-stack text

[wise-king-sullyman]

Closes #4257

[patternfly-build]

Preview: https://patternfly-org-pr-4397-site.surge.sh

[edonehoo]

🎉 looks good to me!

[edonehoo]

Looks good! Especially React/HTML pages

Only thing I noticed is that it seems like the spacing above some headings is a little larger (I think mainly h3 and h4's?) For example, here's the current spacing between two headings:

vs in this pr:

It's more obvious on text-heavy pages (like /about accessibility), but it's still subtle so I don't know if it really matters.

Either way, may be good for a designer's eye to agree with the spacing styling in general --- @andrew-ronaldson could you poke around the preview link and make sure everything feels good?

[kmcfaul]

@wise-king-sullyman Looks like it needs a rebase before the build/synk clears

[wise-king-sullyman]

@mcoker were you planning on making any more changes to this after the previous feedback?

[mcoker]

@wise-king-sullyman In a perfect world, yes, but I've been busy with other priority work. What are you thinking about handling this issue? Anything in particular you have a question about or would like me to look at?