Instead of a bright red for unpublished, use a light gray

Hi, I realise that this is not a "fix" per se, but I'd like to propose with this PR that instead of bright red indicators in the tree for unpublished pages, we instead use a light gray.

To me, a bright red indicator means "something is wrong/broken" or serves to warn that something may get deleted. Gray seems a better color to represent "this is ineffective in its current state".

Indeed, I have clients (well, one so far anyway) who instinctively attempt to fix what is broken by clicking these indicators, and when asked why, explained that he feels like their site is broken until these red dots go away.  Sometimes, pages just aren't ready to be published, nothing broken about that.

Does anyone else have an opinon about this?