RFR 8182776/8183161/8183251: Miscellaneous API doc fixes

[mark.reinhold at oracle.com]

2017/6/30 16:08:09 -0700, jonathan.gibbons at oracle.com:
> Mark,
> 
> The font-family settings in the <dl> nodes were deliberate, and a 
> workaround for not having time to create a proper taglet for tool guides.
> 
> If you remove the style attribute, you'll see in your sample output that 
> the "Tool Guides" header is in Serif font, but the immediately following 
> "Since: "  header is in the standard Sans Serif font.
> 
> See, for example, this page:
> http://cr.openjdk.java.net/~mr/rev/8182776/api/jdk.compiler-summary.html

You're right, but the problem with placing the style attribute on the
`<dl>` elements is that it forces the `<dd>` text into the sans-serif
font.  That's fine for the tool-guide links, since they're tool names,
but it's wrong for provider descriptions, which are free text (see the
attached image).

The right fix is to repair the Javadoc stylesheet, but the expedient fix
is to tweak the style attributes just where needed, so I've updated the
patch to do the latter:

  http://cr.openjdk.java.net/~mr/rev/8182776/jdk9-dev.patch
  http://cr.openjdk.java.net/~mr/rev/8182776/api/ (sample output)

- Mark