auth-source does not support "host" in .netrc files

* doc/misc/auth.texi (Help for users): Remove mention of "host" in
.netrc files, because it's not supported (bug#33826).
1 job for master in 81 minutes and 5 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Test
failed #2476
test-all

01:21:05

 
Name Stage Failure
failed
test-all Test
make[2]: *** [check-doit] Error 1
Makefile:318: recipe for target 'check-doit' failed
make[2]: Leaving directory '/builds/emacs/emacs/test'
make[1]: *** [check-expensive] Error 2
Makefile:293: recipe for target 'check-expensive' failed
make[1]: Leaving directory '/builds/emacs/emacs/test'
make: *** [check-expensive] Error 2
Makefile:959: recipe for target 'check-expensive' failed
ERROR: Job failed: exit code 1