[SCHEMA] Allow acq-* to relate physio data to MRI data in anat/ as described in #2164

[tstoeter]

The deno based validator did not accept files like sub-01_acq-T1w_physio.tsv.gz located in anat/ and related to the T1w anatomy. This was, because a task was required, which was inherited from rules.files.raw.task.timeseries.entities. The key task is now overridden to optional. Please also see issue #2164 for more information and related patches.

[tsalo]

I think mod might make more sense for this.

[tstoeter]

Thank you, @tsalo, for your suggestion, indeed from reading the specs mod seems more appropriate. I have tested it and received another error:

[ERROR] ENTITY_NOT_IN_RULE Entity not listed as required or optional for files with this suffix
		/sub-11/anat/sub-11_mod-T1w_physio.tsv.gz - mod not in rule rules.files.raw.task.timeseries__anat

I believe, this requires another modification of the schema to fix it.