We can skip jobs by specifying branches or tags to filter and this supports regex. So for example we could ignore any branch that starts with documentation/.
However, once this branch is merged to master, an unnecessary build would commence against master branch. By convention, the merge commit will usually have the previous branch name in the commit title for a merge, so it would be nice to be able to specify:
filters: title: ignore: /^Merge.*documentation\/.*/
If [skip ci] is properly supported (which seems to be in question) we could always add that to the merge title, but we’d prefer not to pollute commit messages with tooling hints. It’s also likely that appending [skip ci] in that specific case is going to be forgotten frequently.