Clang-format sees the text behind `#pragma region` as code and formats it. Instead of stating the copyright and date there, it's now in the comment block right below it. The text "Copyright" is left in the `#pragma region` line, as clang-format sees it as a single identifier.
I took the opportunity to normalize the dates, and add the copyright notice to the source files where it was missing them (except for third-party and the generated resources.h file).
This commits works towards #7289. It includes files that it depends on, or forward declares types when possible. It may seem like this only increases compilation time, but before this commit they depended on the other includes of the source files that use them.
