incubator/format/definition.md: Definition clarifications

[phillipeloher]

Not sure if opening an issue here is appropriate or if there is a better place to put these questions. No real issues to report in this case, just some clarification/documentation questions.

header:

• what is 'source ontology', example?
• for 'sample names used in attribute' - does this include items such as SRA accessions?
• 'small RNA GFF version ' - is that the format of this specification? Or is this a different version?
• Filter tags, really like the concept. Think we should give an example that's not just Pass/Fail. Such as CAUTION(ambiguous sequence, may not be an isomiR)

Attributes:

• Read Name - is this optional when the attribute->expression flags are used?
• Parent - is this precursor name the same as Column 1 precursor name? If so, is it redundant?
• Hits - what is defined as a 'hit'? Is this different than Attributes->Expression?
• Variant - what happens it multiple variants for the same isomiR? Will open up a different issue on this since it's more involved

[lpantano]

Thanks for all this great comments @phillipeloher

I'll answer this in the official repository of the report to avoid duplication:
miRTop/mirGFF3#1