Fix content and style errors on all pages

[ctrueden]

This is a community project.

Comment on pages with known content or style issues here.

There will be a page with a table of all pages left to vet. Stay tuned.

[hinerm]

https://imagej.github.io/develop/rois - broken style and source tags

[MarijaMatejcic]

Is there a place listing which pages have already been checked? Any burning places to start with?

[hinerm]

@MarijaMatejcic definitely!

Here is the page list.

Here is a suggestion on how to pick pages.

[MarijaMatejcic]

Related to update site naming, /update-sites > /sites-general and /sites > /sites might be clearer?