Use `clang-tidy -p . $file -checks='-*,modernize-use-override' -header-filter='.*' -fix`
to fix missing overrides, and then use git clang-format to reformat just
those changes. This went pretty well for most files.
Formatting the following files went off the rails, so I'm going to
follow up with a commit that's just clang-tidy and no clang-format.
- fdbclient/DatabaseBackupAgent.actor.cpp
- fdbclient/FileBackupAgent.actor.cpp
- fdbserver/OldTLogServer_4_6.actor.cpp
- fdbmonitor/SimpleIni.h
- fdbserver/workloads/ClientTransactionProfileCorrectness.actor.cpp
