The title was saying "Unstage lines", which was just wrong. The text said
"Delete lines", which can be seen as a bit misleading; we are only discarding
the changes to the selected lines, not deleting the lines themselves.
For consistency, rename the config variable skipUnstageLineWarning accordingly.
We have not been good at consistent casing so far. Now we use 'Sentence case' everywhere. EVERYWHERE.
Also Removing 'Lc' prefix from i18n field names: the 'Lc' stood for lowercase but now that everything
is in 'Sentence case' there's no need for the distinction.
I've got a couple lower case things I've kept: namely, things that show up in parentheses.
