Docs: No hard breaks in prose

[rxaviers]

In reference of https://github.com/jquery/globalize/pull/321/files#r22041598, where @scottgonzalez said:

The prose style guide is scattered. See jquery/contribute.jquery.org#75.
The rule is no hard breaks in prose.

[rxaviers]

Closing this issue in favor of a super set #471.