No these words don't mean the same thing, that's ok -- "shared" is less specific anyway (partial templates can be shared), and I think at this point we prefer a folder called "overrides" and a folder called either "partials" or "includes," ya?
The only template in "shared" right now is a field template for field_post_date, so that fits for an "overrides" folder.
[x] Create "partials" folder
[x] Split head/foot sections of html.html.twig into head/foot templates (just b/c we do this in child themes kinda every time anyway, right?)
i.e. site-header, site-footer, cu-header, cu-search
[x] Document intended use of "overrides" and "partials" sub-folders.
⚠️ UPDATE: Footer template will have to wait, because cwd_base puts footer stuff in page.html.twig, so we can't put it "in" html.html.twig (by way of site-footer.html.twig).
⚠️ UPDATE: Footer template will have to wait, because cwd_base puts footer stuff in page.html.twig, so we can't put it "in" html.html.twig (by way of site-footer.html.twig).