Add some missing nullable annotations

30 jobs for !1708 with nullable in 4 minutes and 21 seconds (queued for 5 seconds)
detached
Status Job ID Name Coverage
  Build Docker
passed #5055551
alpine amd64 manifest builder docker

00:00:29

passed #5055550
android docker

00:00:25

passed #5055549
cerbero fedora amd64 docker

00:00:29

passed #5055548
fedora amd64 docker

00:04:02

passed #5055552
gst-indent amd64 docker

00:00:30

 
  Preparation
passed #5055554
gst indent

00:00:19

manual #5055553
manual
manifest
 
  Build
created #5055563
gstreamer
build cerbero cross-android universal
created #5055567
gst-ios-13.2
build cerbero cross-ios universal
created #5055564
gstreamer
build cerbero cross win32
created #5055565
gstreamer
build cerbero cross win64
created #5055562
gstreamer
build cerbero fedora x86_64
created #5055566
gst-macos-10.15
build cerbero macos x86_64
created #5055568
1809 gstreamer-windows windows docker
build cerbero msvc x86_64
created #5055558
build clang fedora x86_64
created #5055561
1809 windows docker allowed to fail manual
build msys2
created #5055555
build nodebug fedora x86_64
created #5055556
build static fedora x86_64
created #5055557
build static nodebug fedora x86_64
created #5055559
1809 windows docker
build vs2017 amd64
created #5055560
1809 windows docker
build vs2017 x86
 
  Test
created #5055569
gstreamer
check fedora
created #5055570
gstreamer
integration testsuites fedora 1/4
created #5055571
gstreamer
integration testsuites fedora 2/4
created #5055572
gstreamer
integration testsuites fedora 3/4
created #5055573
gstreamer
integration testsuites fedora 4/4
created #5055574
gstreamer
valgrind bad
 
  Integrate
created #5055575
cross-android universal examples
created #5055577
gst-ios-13.2
cross-ios universal examples
created #5055576
documentation