PR: Rename Related Components to Related Panes for clarity

[CAM-Gerlach]

Pull Request

Pull Request Checklist

• [x] Read and followed this repo's Contributing Guidelines
• [x] Based your PR on the latest version of the correct branch (master or 4.x)
• [x] Checked your writing carefully for correct English spelling, grammar, etc
• [x] Described your changes and the motivation for them below

Description of Changes

As originally noticed on #322 , the choice of name in the standard "Related components" heading is not ideal—"Related panes" is more clear and specific, shorter, and avoids confusion with any other use of components within the section titles, e.g. as on #322 . Therefore, we should change it. I've updated the style guide accordingly.

[ccordoba12]

@CAM-Gerlach, this PR contains some images that I think don't belong here but are part of PR #322, right?

[CAM-Gerlach]

Wow, thanks for the catch @ccordoba12 — some untracked files from my image optimization on that PR got picked up here and somehow I missed that at every step. I'm usually careful to check that as that would have been a really bad mistake. Fixed now, and I cleaned my workding dir so it won't happen again.