RFR: JDK-8241693,The paragraphs in the help page should not be in a <ul>

[Jonathan Gibbons]

Please review a simple webrev to eliminate the inappropriate use of a 
<ul> list for the series of <section> elements on the help page.

This <ul> is also one of the instances of the "block-list" CSS class we 
are trying to clean up, so removing the list fixes that usage!

Just removing the list was almost too easy, so I took the opportunity to 
cleanup/simplify the code, using some of the recent new API for chained 
method calls.

Simply removing the `<ul class="block-list">` did affect the whitespace 
layout of the page for the bulleted lists. While the bulleted lists 
previously used simple `<ul>` they inherited margins from the enclosing 
`<ul class="block-list">` (which is now removed). This was fixed by 
setting the class name of the bulleted lists to a new class, 
`help-section-list`, with an appropriate definition in the stylesheet, 
to restore the whitespace appearance of the lists on the page.

I also took the opportunity to rename the poorly-named 
`emphasized-phrase` to `help-footnote` to better denote its usage.

Apart from removing the <ul> and corresponding <li> items, there are no 
other changes to the visible content of the page. The source of the 
generated page was compared, with meld, against the version of the page 
before the change. In addition to that manual test, the 
TestHelpFile.java test was updated with a simple check for a 
representative sample of the content of the page, and specifically for 
the lack of the list elements surrounding the individual sections.

-- Jon

JBS: https://bugs.openjdk.java.net/browse/JDK-8241693
Webrev: http://cr.openjdk.java.net/~jjg/8241693/webrev.00/
API: http://cr.openjdk.java.net/~jjg/8241693/api.00/help-doc.html