imcontext: Take out the warnings

Don't warn about Compose file constructs we don't
support. We haven't supported these for a long time,
and nobody has every complained. No need to wake
up sleeping dogs.
7 jobs for compose-warning-3 in 22 minutes and 15 seconds (queued for 3 seconds)
Status Name Job ID Coverage
  Build
passed debian-meson #1171260

00:08:00

passed fedora-autotools #1171257

00:09:08

manual fedora-distcheck #1171258
allowed to fail manual
passed fedora-meson #1171259

00:10:21

manual msys2-mingw64-autotools #1171262
win32-ps allowed to fail manual
passed msys2-mingw64-meson #1171261
win32-ps

00:03:30

 
  Docs
passed reference #1171263

00:08:23