Use a more explicit description for the modified files dialog option
The first commit changes the option text of Warn about files modified by foreign processes
to Use a separate &dialog for handling externally modified files
since the original text implies that disabling the option will result into
no warnings for files modified by foreign processes.
The 2nd commit uses a hack so that the modified files dialog does not steal focus. The downside is that it is very hacky (it uses show() instead of exec(), so the dialog does not block) and the dialog is no longer modal (it still stays in front of the main window, but it won't prevent users from writing text).
CCBUG: 353712 GUI:
Personally, I think only the first commit is needed considering how hacky the 2nd commit is. I couldn't find any other way to not steal focus (not even Qt::WA_ShowWithoutActivating
works) without delaying the warning itself.