In HTML output, in cells with an "n" (number) layout, pad numbers

In HTML output, in cells with an "n" (number) layout, pad numbers
on the right side with UTF-8 punctuation and figure spaces such
that numbers in different tbl(7) rows align at the decimal point.

The exact HTML output format was suggested
by <Oliver dot Corff at email dot de>;
the implementation in C is mine.