Add various missing nullable annotations

10 jobs for missing-nullable in 29 minutes and 59 seconds (queued for 1 second)
Status Job ID Name Coverage
  Style Check
passed #944664
check-todos

00:29:59

passed #944663
style-check-diff

00:01:33

 
  Build
passed #944667
cross-android_api21_arm64

00:02:06

passed #944668
cross-android_api28_arm64

00:02:02

passed #944669
cross-mingw64

00:02:29

passed #944666
debian-stable-x86_64

00:02:44

passed #944665
fedora-x86_64

00:10:08

passed #944670
win32-ps
msys2-mingw32

00:09:09

passed #944671
win32-ps
vs2017-x64

00:07:02

 
  Coverage
passed #944672
coverage

00:01:23

75.5%