D-sub connectors should use correct shell names

[henryhallam]

Presently in the Connectors library all the D-sub connectors are named with a "DB" prefix, which is incorrect except for DB-25. The second letter should specify the shell size. Further, there should be a hyphen between the shell size letter and the number of pins. See wikipedia for background.

e.g.:

Is	Should be
DB9_Female	DE-09_Female
DB15_Male	DA-15_Male
DB15_Male_HighDensity	DE-15_Male

Since this is a common confusion, it would be reasonable to add e.g. DB9 DB-9 DE9 DE-9 to the keywords for the DE-09, and to specify in the description whether the connector uses standard or high density pin spacing.

[evanshultz]

Yeah. Good catch and thanks for making this issue. I think what you propose sounds good.

Also, this issue affects footprints at https://github.com/KiCad/kicad-footprints/tree/master/Connector_Dsub.pretty which aren't following the correct naming convention either. It appears that https://github.com/pointhi/kicad-footprint-generator/blob/master/scripts/Connectors_DSub/make_dsubs.py may be able to make the footprints so updating them shouldn't be too tough.

In addition, I would like to have a quality document for this family of connectors. https://disti-assets.s3.amazonaws.com/tonar/files/datasheets/16730.pdf is in the footprints but it's less than thorough. https://www.ckswitches.com/media/1857/mil-24308-class-m-qpl.pdf looks like a better one.

Renaming symbols and footprints could break existing KiCad designs so the timing of this should be considered carefully. @poeschlr After 5.0.2 is released, to be integrated into 5.1's release libraries?

[antoniovazquezblanco]

This would fully break working designs just to conform to a standard. Maybe it would be better not to rush this and postpone to 6.0.0