Resolve the six unanswered copy-editor "AU:" queries left in the source

[kgdunn]

From the hidden-RST-comment scan (author notes not visible in the HTML/PDF). A professional copy-edit pass left "AU:" (author query) comments that were never answered. Each needs a decision, possibly a sweep, then removal of the comment. Permalinks pinned to commit 65760be.

1. AU: I am taking "section" to mean, e.g., "1.2 Usage examples". In the following sentence and elsewhere, I change it to "chapter" if appropriate.
data-visualization/data-visualization-in-context.rst L17 - confirm the section/chapter wording is now consistent.

2. AU: Do you have publication dates for the Few books?
data-visualization/data-visualization-in-context.rst L54 - Stephen Few: Show Me the Numbers (2004, 2nd ed. 2012), Information Dashboard Design (2006), Now You See It (2009). Add the dates where the books are cited.

3. AU: In this chapter, page references to section links are shown as "page 279". I have been using "p. 279" in previous chapters. To be consistent, please either change the format...
design-analysis-experiments.rst L324 - pick one convention ("page" vs "p.") and sweep all chapters.

4. AU: It would be nice to italicize the individual terminology words (outcome, factor, objective, etc.) ... But italicizing doesn't seem to be compatible with :index:. Is there a way to make it work?
design-analysis-experiments.rst L352 - Sphinx supports this: write *term* in the text with a separate .. index:: directive above the paragraph, or a custom role. Decide and apply.

5. AU: I inserted the two main ways. Please confirm.
assessing-significance-of-main-effects-and-interactions.rst L12`` - note: the rendered sentence below it now says three ways (Pareto/Lenth, and standard error) after the recent Lenth's-method PR, so this comment is stale; confirm and delete.

6. AU: I modified the last sentence of the following paragraph because it seemed redundant. Please confirm.
assessing-significance-of-main-effects-and-interactions.rst L244`` - read the paragraph, confirm the edit stands, delete the comment.