S5.1 error for single footprint filter and no default footprint
I see many symbols that get hit with an error from Travis of Symbol has a single fooprint filter string '<single footprint filter>' (i.e. it seems to be intended for a single default footprint only), but the footprint field is empty. Fill footprint field with the correct footprint in the form LIBRARY:FOOTPRINT.
This is from line 91 of https://github.com/KiCad/kicad-library-utils/blob/master/schlib/rules/S5_1.py, which only occurs if there is no default footprint and just a single footprint filter entry. This is correct in many libraries (such as generic connector symbols) and to me an error seems too strong. Even the wording, by using "seems", isn't forceful. It is a worthwhile situation to catch and report, and a warning would give us that while not complaining in cases where this rule definitely does not apply.
Should this just be a warning and not an error?
Lastly, as you can see above, line 93 has a typo of "footprint" by missing the first "t".