Ticket #4915: Fix the help window's title color

[egmontkob]

This broke in recent commit e99555c.

Proposed changes

Use named indices rather than just listing the struct items which can easily go out of sync.

For consistency, moved the code to where other similar structs are initialized.

• Resolves: master: Help's title color broken #4915

Checklist

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• I have referenced the issue(s) resolved by this PR (if any)
• I have signed-off my contribution with git commit --amend -s
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• I have added tests that prove my fix is effective or that my feature works
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[mc-worker]

help_colors is still used in the help_interactive_display() function only. Why did you introduce a global variable instead of fixing the local one?

[egmontkob]

listbox_colors is also only used at one place, yet is defined globally. Thus moving help_colors here makes the code more consistent: fewer different patterns seen at how various dlg_colors_t structures are defined.

The old code layout here is obviously pretty fragile; if I simply added a few new members to the current assignment then it could easily break later on, just as it did now. So I definitely wanted to have a syntax where each value is clearly assigned to its proper and explicitly spelled out index. Keeping help_colors's assignment at its current location would only have been possible using runtime (i.e. non-const) assignment which is run over and over again, something that seems to me isn't really liked by mc's current coding practice. help.c doesn't have an init() method either where I could have convenienently moved this initialization to.

Does this make sense? If you don't like the proposed design then please give clear instructions what would be your preferred solution.