Format Number of Missed Signatures as Fraction

It would be nice to change the format that missed signatures is displayed in, and/or add context to it. The raw number can be useful in some cases, but there are also plenty of times where the raw number alone doesnt give enough information.

It would be good to instead display that value as a fraction (ex: 20 / 50), so that when looking at it, we know how many possible signatures there were.

Search the Flask evaluation views and templates for where missed signatures are displayed, then trace how the current value is calculated. The work is done when the display provides the missed count together with the possible-signature count, such as “20 / 50,” and existing evaluation views still render correctly.

Written by the indexing model from the issue text.