Fix comments of Freagarach

Fix linter. Ready for review.

Fix tests and prepare for D4217

To nip all discussions in the butt, I propose the following:

At the moment the idle time uses the same units as the "Idle Worker Button". More precisely, it counts all units which satisfy at least one of the following classes

["FemaleCitizen", "Trader", "FishingBoat", "Citizen"];

This sounds _very_ expensive?

In D3940#169812, @Langbart wrote:

I received some errors when trying to access the Population--> Total chart for a replay I did in multiplayer. I attach the file: 6_may_21.zip

"I guess it is either this or a revert. I don't like the fact that we filter here, I think we should do it earlier, if one has hideInSummary true for the counter, but not for the heading things get ugly again."

@Freagarach
See #5940.
If I find the time I can implement these as well. But first, I think suggestion are welcome.

@Stan Good thing about the ternary operator: the branch that will not be picked won't be evaluated. So the new object (with no resources) will only be build when this function is called without a player (which is rare).

Fix: comments from Stan

I changed hide to the more informative hideInSummary.

Fixing some linter details

In D3395#150799, @Angen wrote:

I did quick test and noticed, that if resource is not used or gathered, total count is not recorded.

Typo fix and better variablename

fixing comments from angen