Write list for sanity checks when making doc updates

[rmglennon]

Let's make a checklist for some basic manual sanity testing when making updates to the documentation, particularly with style changes.

(starting this as an issue, and maybe we can port to style guide with links to pages exhibiting these to make the testing quicker)

cc @louh @migurski

Examples of things to verify:

Navigation between topics with bottom arrows works Breadcrumbs appear and are links Edit on GitHub page links goes to markdown files Simple search returns results Scroll with mouse on page scrolls the TOC TOC entries can be clicked to scroll page Resize browser window

Formatting: Page banner headings Subheadings and other fonts Code blocks In-line code Steps and ordered lists Unordered lists Images Tables