Merge branch 'aqualls-child-span-language' into 'master'

Change 'children spans' to 'child spans'

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/135623



Merged-by: Jose Ivan Vargas <jvargas@gitlab.com>
Approved-by: Daniele Rossetti <drossetti@gitlab.com>
Approved-by: Alex Pennells <apennells@gitlab.com>
Approved-by: Jose Ivan Vargas <jvargas@gitlab.com>
Co-authored-by: Amy Qualls <aqualls@gitlab.com>