Comments in between <pre> tags are not indented properly because the doclet
does not know how many spaces to replaces tabs with. We already have an
*undocumented* option -linksourcetab to specify the number of spaces for
each tab in source files that works with the -linksource option.
These pages are entirely in the <pre> tags. We should make the -linksourcetab
option more general (and rename it to -sourcetab) so that it can be used in other ways.

Also, if a developer uses tab characters to align columns
similar to a table, these should also be converted to spaces.
This implies converting tabs globally throughout the comment.