Greying/strikethrough in initial table is misleading for old-release-only errors

The default table on <https://errors.ubuntu.com/> shows the reported errors that most affect users of Ubuntu overall. This is an important guide to which problems most affect Ubuntu users in the real world, including those who haven't upgraded to the latest Ubuntu release.

However, this causes confusion when styling the rows.

Imagine for example that:
* Ubuntu 12.04 LTS was released with foobar 1.0
* Ubuntu 12.10 was released with foobar 2.0
* the same common crash affects both versions.

If the crash is fixed in 2.0.1 but not in 1.x, then the overall table will show it with strikethrough (if it was marked fixed) or greyed out (if it wasn't), despite the fact that it's still occurring for Ubuntu 12.04 users who have no fixed version to update to.

In either case, if it's still appearing in the overall table, it's still affecting many Ubuntu users. So the appropriate thing to do is probably not to ignore it, but to fix it in 12.04 as well. Therefore, using strikethrough or greying out is misleading.

The easy way to fix this is to neither grey out nor strike through problems if the table is showing problems across Ubuntu releases. Style them only when the table is showing problems for one Ubuntu release.

The hard way to fix it is to grey out problems only when they haven't been observed in the latest version of the package in *any* of the Ubuntu releases the table is currently showing.

(This problem does not extend to the highlighting of regressions. If the example crash was fixed only in 1.0.1 but not in 2.x, so 2.0 seemed to be a "later" version containing the problem, that would still indicate a mistake in the development process, even if it's not a regression per se.)