Consider introducing line breaks after each sentence

[cygnusv]

Single line breaks are ignored by Markdown, so they're effectively equivalent to spaces. However, this has the advantage that future changes are more surgical, since often changes only affect a single sentence (or perhaps, the sentences just above or below), which facilitates reviews a lot. Currently, most lines in the docs contain full paragraphs, so a single letter change in a paragraph is rendered by diff viewers as affecting the complete paragraph.

We can do this iteratively, so eventually all the code follows the same convention.