lists.scss: reset <ol> without 'type' attr to "decimal"
lists.scss: reset <ol> without 'type' attr to "decimal"

HTML default list-style-type is "decimal" when there is no 'type'
attribute.

In MarkDown language, you can't specify the style type of a list
item, so nested lists *always* represent with decimal numbers at
any level. Since this is not user friendly, GitHub CSS styling
overrides the HTML standard by setting lower-roman for second-level
items and lower-alpha for third-level items.

In AsciiDoc language, you can specify the style type of a list
item using a tage before the list, for example:

   Tag		    Produces
   [loweralpha]     <ol type="a">
   [lowerroman]     <ol type="i">
   [decimal]        <ol>

The [decimal] tag doesn't generate any 'type' attribute because
the HTML standard when there is no type, *is* decimal.
If such a [decimal] tag is used on a second-level or third-level
item, GitHub CSS for MarkDown overrides HTML standard and you get
instead a lowerroman or loweralpha sign.

The added CSS resets the list-style-type of <ol> without type to
decimal, as it should be in the first place, for the construction
div > ol, which is only produced by AsciiDoc files, to avoid any effect
on existing MarkDown files.

Signed-off-by: Hector Palacios <a8c4a54ab41b1fd5344b908edc2fcb81d5f78d9f@digi.com>

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