Missing Report: change column title from "Details" to "Value found in other locales"

[weedySeaDragon]

I think the output will be clearer for themissing report if you change the column title from "Details" to "Value found in other locales". This will help new users and will reduce misunderstandings like in #127.

You could also (or as an alternative) add an information line in the output after the print-title line that explains the output. This could be something like "These are the locales that are missing keys and values that exist in other locales. The list shows a value found for the key in another locale."

This is great work (and lovely code). I can help with bits of documentation if that's useful: on the wiki here, adding examples in the command descriptions, etc.