Checklist

Required

• I wrote the PR title in conventional commit format.
• I ran the code formatter.
• I linked any relevant issues using github keyword syntax so it can be closed automatically.
• I have committed my changes to new branch that isn't main so it won't cause conflict when updating main branch later.

Optional

Purpose of change

UI improvement for the kill counter added in #5394. @RoyalFox2140 asked me to recolor the Kills button in the examine item menu to make it a bit more visible. While looking through the menu code, I also figured out a way to add a kill counter in the menu, which I'd wanted to have since the beginning.

Describe the solution

The Kills menu option was given its own hint color (red). The add_entry() function in examine_item_menu.cpp was modified to optionally print a number in addition to menu text.

Describe alternatives you've considered

I think dark red has the appropriate connotations of violence, but changing the color is easy if someone has a better idea. Light red is already used in the menu in a different context, but yellow for example might work.

Thought about adding a new add_entry_with_number function instead of overloading the existing one, but that would have meant copypasting the whole thing.

Testing

Loaded save with items with recorded kills. Menu option appears correctly. Menu option does not appear for items with no kills. Counted list entries to double check number is correct.

Additional context

Before:

After: