Clarify whether there is a stated preference regarding headings with sections

[travisleithead]

Copied from Bugzilla: https://www.w3.org/Bugs/Public/show_bug.cgi?id=25270

4.3.6 The h1, h2, h3, h4, h5, and h6 elements

"Authors might prefer the former style for its terseness, or the latter style for its convenience in the face of heavy editing; which is best is purely an issue of preferred authoring style."

4.3.10 Headings and sections

"Authors are also encouraged to explicitly wrap sections in elements of sectioning content, instead of relying on the implicit sections generated by having multiple headings in one element of sectioning content."

The first quote implies that there is no suggested style, while the latter quote prefers one style over the other. I have no idea what the consensus is.

[chaals]

This is a redundant part of #169 which itself is a part of #33.