copyright header typos
There has been a typo in our copyright header message for a long time; also an "http" link that should have been "https". @sgoldlust fixed it in a few files in !4118 (merged), which I merged by accident before realizing that some of the changes she'd made were in automatically generated text. This MR corrects the COPYRIGHT files from which the text is taken, and updates all headers throughout the tree to match.